SCHEDULE 13G  
  
Amendment No. 2  
Lam Research Corporation  
Common Stock  
Cusip # 512807108  
Filing Fee: No  
 
 
Cusip # 512807108  
Item 1:	Reporting Person - FMR Corp. - (Tax ID:  04-2507163)  
Item 4:	Commonwealth of Massachusetts  
Item 5:	46,500  
Item 6:	None  
Item 7:	815,100  
Item 8:	None  
Item 9:	815,100  
Item 11:	2.98%  
Item 12:	HC   
  
  
 
 
Cusip # 512807108  
Item 1:	Reporting Person - Edward C. Johnson 3d - (Tax ID:  029-24-9996)  
Item 4:	United States of America  
Item 5:	None  
Item 6:	None  
Item 7:	815,100  
Item 8:	None  
Item 9:	815,100  
Item 11:	2.98%  
Item 12:	IN   
  
  
 
 
SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS  
FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)  
  
  
Item 1(a).	Name of Issuer:  
  
		Lam Research Corporation  
  
Item 1(b).	Name of Issuer's Principal Executive Offices:  
  
		4650 Cushing Parkway   
		Fremont, CA  94538  
  
Item 2(a).	Name of Person Filing:   
  
		FMR Corp.  
  
Item 2(b).	Address or Principal Business Office or, if None, Residence:  
  
		82 Devonshire Street, Boston, Massachusetts  02109  
  
Item 2(c).	Citizenship:  
  
		Not applicable  
  
Item 2(d).	Title of Class of Securities:  
  
		Common Stock  
  
Item 2(e).	CUSIP Number:    
  
		512807108  
  
Item 3.	This statement is filed pursuant to Rule 13d-1(b) or 13d-2(b) and the  
person filing, FMR Corp., is a parent holding company in accordance  
with Section 240.13d-1(b)(ii)(G).  (Note:  See Item 7).  
  
Item 4.	Ownership  
  
	(a)	Amount Beneficially Owned: 
	815,100  
  
	(b)	Percent of Class: 
	2.98%  
  
	(c)	Number of shares as to which such person has:    
  
	(i)	sole power to vote or to direct the vote: 
	46,500  
  
	(ii)	shared power to vote or to direct the vote: 
	None  
  
	(iii)	sole power to dispose or to direct the disposition of: 
	815,100  
  
	(iv)	shared power to dispose or to direct the disposition of: 
	None  
  
  
 
 
Item 5.	Ownership of Five Percent or Less of a Class.  
  
	If this statement is being filed to report the fact that as of  
the date hereof, the reporting person has ceased to be the  
beneficial owner of more than five percent of the class of  
securities, check the following (X).  
  
Item 6.	Ownership of More than Five Percent on Behalf of Another Person.  
  
	Not applicable.  
  
Item 7.	Identification and Classification of the Subsidiary Which Acquired  
the Security Being Reported on By the Parent Holding Company.  
  
	See attached Exhibit(s) A, B, and C.  
  
Item 8.	Identification and Classification of Members of the Group.  
  
	Not applicable, see attached Exhibit A.   
  
Item 9.	Notice of Dissolution of Group.  
  
	Not applicable.  
  
Item 10.	Certification.  
  
	Inasmuch as the reporting persons are no longer the beneficial  
owners of more than five percent of the number of shares  
outstanding, the reporting persons have no further reporting  
obligation under section 13(d) of the Securities and Exchange  
Commission thereunder, and the reporting persons have no  
obligation to amend this Statement if any material change  
occurs in the facts set forth herein.  
  
  
Signature  
  
	After reasonable inquiry and to the best of my knowledge and  
belief, I certify that the information set forth in this  
Schedule 13G in connection with FMR Corp's beneficial ownership  
of the common stock of Lam Research Corporation at November 30,  
1995 is true, complete and correct.   
  
  
  
	December 7, 1995	  
Date  
  
  
  
	/s/Arthur S. Loring  
Signature  
  
  
  
	Arthur S. Loring, Vice  
President	  
Name/Title  
  
  
 
 
SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS  
FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)  
  
	Pursuant to the instructions in Item 7 of Schedule 13G, Fidelity  
Management & Research Company ("Fidelity"), 82 Devonshire Street, Boston,  
Massachusetts 02109, a wholly-owned subsidiary of FMR Corp. and an investment  
adviser registered under Section 203 of the Investment Advisers Act of 1940,  
is the beneficial owner of 768,600 shares or 2.81% of the common stock  
outstanding of Lam Research Corporation ("the Company") as a result of acting  
as investment adviser to several investment companies registered under Section  
8 of the Investment Company Act of 1940.    
  
	Edward C. Johnson 3d, FMR Corp., through its control of Fidelity, and the  
Funds each has sole power to dispose of the 768,600 shares owned by the Funds.  
  
	Neither FMR Corp. nor Edward C. Johnson 3d, Chairman of FMR Corp., has  
the sole power to vote or direct the voting of the shares owned directly by  
the Fidelity Funds, which power resides with the Funds' Boards of Trustees.   
Fidelity carries out the voting of the shares under written guidelines  
established by the Funds' Boards of Trustees.  
  
	Members of the Edward C. Johnson 3d family are the predominant owners of  
Class B shares of common stock of FMR Corp. representing approximately 49% of  
the voting power of FMR Corp.  Mr. Johnson 3d owns 12.0% and Abigail Johnson  
owns 24.5% of the aggregate outstanding voting stock of FMR Corp., and Mr.  
Johnson 3d is Chairman of FMR Corp.  The Johnson family group and all other  
Class B shareholders have entered into a shareholders' voting agreement under  
which all Class B shares will be voted in accordance with the majority vote of  
Class B shares.  Accordingly, through their ownership of voting common stock  
and the execution of the shareholders' voting agreement, members of the  
Johnson family may be deemed, under the Investment Company Act of 1940, to  
form a controlling group with respect to FMR Corp.  
  
	Fidelity International Limited, Pembroke Hall, 42 Crowlane, Hamilton,  
Bermuda, and various foreign-based subsidiaries provide investment advisory  
and management services to a number of non-U.S. investment companies (the  
"International Funds") and certain institutional investors.  Fidelity  
International Limited is the beneficial owner of 46,500 shares or 0.17% of the  
common stock outstanding of the Company.  Additional information with respect  
to the beneficial ownership of Fidelity International Limited is shown on  
Exhibit B, page 8.  
 
 
SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS  
FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)  
  
  
	Pursuant to instructions in Item 7 of Schedule 13G, this Exhibit has been  
prepared  to identify Fidelity International Limited, Pembroke Hall, 42 Crow  
Lane, Hamilton, Bermuda, a Bermudian joint stock company incorporated for an  
unlimited duration by private act of the Bermuda Legislature (FIL) and an  
investment adviser to various investment companies (the "International Funds")  
and certain institutional investors, as a beneficial owner of the 46,500  
shares or 0.17% of the common stock outstanding of Lam Research Corporation.  
  
	Prior to June 30, 1980, FIL was a majority-owned subsidiary of Fidelity  
Management & Research Company (Fidelity), a wholly-owned subsidiary of FMR  
Corp.  On that date, the shares of FIL held by Fidelity were distributed, as a  
dividend,  to the shareholders of FMR Corp.  FIL currently operates as an  
entity independent of FMR Corp. and Fidelity.  The International Funds and  
FIL's other clients, with the exception of Fidelity and an affiliated company  
of Fidelity, are non-U.S. entities.  
  
	A partnership controlled by Edward C. Johnson 3d and members of his  
family owns shares of FIL voting stock with the right to cast approximately  
47.22% of the total votes which may be cast by all holders of FIL voting  
stock.  Mr. Johnson 3d is Chairman of FMR Corp. and FIL.  FMR Corp. and FIL  
are separate and independent corporate entities.  FMR Corp. and FIL are  
managed independently and their Boards of Directors are generally composed of  
different individuals.  Other than when one serves as a subadviser to the  
other, their investment decisions are made independently, and their clients  
are different organizations.  
  
	FMR Corp. and FIL are of the view that they are not acting as a "group"  
for purposes of Section 13(d) under the Securities Exchange Act of 1934 (the  
"1934" Act) and that they are not otherwise required to attribute to each  
other the "beneficial ownership" of securities "beneficially owned" by the  
other corporation within the meaning of Rule 13d-3 promulgated under the 1934  
Act.  Therefore, they are of the view that the shares held by the other  
corporation need not be aggregated for purposes of Section 13(d). However, FMR  
Corp. is making this filing on a voluntary basis as if all of the shares are  
beneficially owned by FMR Corp. and FIL on a joint basis.  
  
	FIL may continue to have the International Funds or other accounts  
purchase shares subject to a number of factors, including, among others, the  
availability of shares for sale at what FIL considers to be reasonable prices  
and other investment opportunities that may be available to the International  
Funds.  
  
	FIL intends to review continuously the equity position of the  
International Funds and other accounts in the Company.  Depending upon its  
future evaluations of the business and prospects of the Company and upon other  
developments, including, but not limited to, general economic and business  
conditions and money market and stock market conditions, FIL may determine to  
cease making additional purchases of shares or to increase or decrease the  
equity interest in the Company by acquiring additional shares, or by disposing  
of all or a portion of the shares.  
  
	FIL does not have a present plan or proposal which relates to or would  
result in (i) an extraordinary corporate transaction, such as a merger,  
reorganization, liquidation, or sale or transfer of a material amount of  
assets involving the Company or any of its subsidiaries, (ii) any change in  
the Company's present Board of Directors or management, (iii) any material  
changes in the Company's present capitalization or dividend policy or any  
other material change in the Company's business or corporate structure, (iv)  
any change in the Company's charter or by-laws, or (v) the Company's common  
stock becoming eligible for termination of its registration pursuant to  
Section 12(g)(4) of the 1934 Act.  
  
	FIL has the sole power to vote and the sole power to dispose of 46,500  
shares.    
 
 
SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS  
FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)  
  
RULE 13d-1(f)(1)  AGREEMENT  
  
	The undersigned persons, on December 7, 1995, agree and consent to the  
joint filing on their behalf of this Schedule 13G in connection with their  
beneficial ownership of the common stock of Lam Research Corporation at  
November 30, 1995.  
  
	FMR Corp.  
	By	/s/Arthur S. Loring  
Arthur S. Loring 
Vice President - Legal  
	Edward C. Johnson 3d  
	By	/s/Arthur S. Loring  
Arthur S. Loring 
Under Power of Attorney dated  
5/17/89 
On File with Schedule 13G for 
Airborne Freight Corp. 9/10/91  
	Fidelity Management & Research Company  
	By	/s/Arthur S. Loring  
Arthur S. Loring 
Sr. V.P. and General Counsel