SCHEDULE 13G

Amendment No. 0 
Gildan Activewear Incorporated 
Class A Subordinate Voting Shares 
Cusip # 375916103                

Cusip # 375916103           
Item 1:	Reporting Person - FMR Corp.
Item 4:	Commonwealth of Massachusetts
Item 5:	0 
Item 6:	0 
Item 7:	929,000 
Item 8:	0 
Item 9:	929,000 
Item 11:	12.643% 
Item 12:	    HC

Cusip # 375916103    
Item 1:	Reporting Person - Edward C. Johnson 3d 
Item 4:	United States of America
Item 5:	0 
Item 6:	0 
Item 7:	929,000 
Item 8:	0 
Item 9:	929,000 
Item 11:	12.643% 
Item 12:	IN 

Cusip # 375916103      
Item 1:	Reporting Person - Abigail P. Johnson 
Item 4:	United States of America
Item 5:	None 
Item 6:	None 
Item 7:	929,000 
Item 8:	None 
Item 9:	929,000 
Item 11:	12.643% 
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:	

		Gildan Activewear Incorporated 

Item 1(b).	Name of Issuer's Principal Executive Offices:

		725 Montee de Liesse, Ville Saint-Laurent 
		Quebec, H4T 1P5  Canada  

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:

		Class A Subordinate Voting Shares 

Item 2(e).	CUSIP Number:  

		375916103 

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:	929,000 

	(b)	Percent of Class:	12.643% 

	(c)	Number of shares as to which such person has:  

	(i)	sole power to vote or to direct the vote:	0 

	(ii)	shared power to vote or to direct the vote:	0 

	(iii)	sole power to dispose or to direct the disposition of:
	929,000 

	(iv)	shared power to dispose or to direct the disposition of:
	0 




Item 5.	Ownership of Five Percent or Less of a CommonStock.

	Not applicable.

Item 6.	Ownership of More than Five Percent on Behalf of Another 
Person.

	Various persons have the right to receive or the power to direct 
the receipt of dividends from, or the proceeds from the sale of, the 
Class A Subordinate Voting Shares of Gildan Activewear Incorporated.  
The interest of one person, Fidelity Canadian Growth Company Fund, an 
investment company registered under the Investment Company Act of 1940, 
in the Class A Subordinate Voting Shares of Gildan Activewear 
Incorporated, amounted to 500,000 shares or 6.805% of the total 
outstanding Class A Subordinate Voting Shares at April 30, 1999. 

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. 

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.

	By signing below I certify that, to the best of my knowledge and 
belief, the securities referred to above were acquired in the ordinary 
course of business and were not acquired for the purpose of and do not 
have the effect of changing or influencing the control of the issuer of 
such securities and were not acquired in connection with or as a 
participant in any transaction having such purpose or effect.
	
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 Class A 
Subordinate Voting Shares of Gildan Activewear Incorporated at April 
30, 1999 is true, complete and correct. 

	May 10, 1999 
Date


	/s/Eric D. Roiter
Signature


	Eric D. Roiter	
	Duly authorized under Power of Attorney
	dated December 30, 1997, by and on behalf
	of FMR Corp. and its direct and indirect
	subsidiaries



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 929,000 shares or 
12.643% of the Class A Subordinate Voting Shares outstanding of Gildan 
Activewear Incorporated  ("the Company") as a result of acting as 
investment adviser to various investment companies registered under 
Section 8 of the Investment Company Act of 1940.

	The ownership of one investment company, Fidelity Canadian Growth 
Company Fund, amounted to 500,000 shares or 6.805% of the Class A 
Subordinate Voting Shares outstanding. Fidelity Canadian Growth Company 
Fund has its principal business office at 82 Devonshire Street, Boston, 
Massachusetts 02109.

	Edward C. Johnson 3d, FMR Corp., through its control of Fidelity, 
and the funds each has sole power to dispose of the 929,000 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.  Mr. Johnson 3d is Chairman of FMR Corp. and 
Abigail P. Johnson is a Director 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.

 


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 May 10, 1999, agree and consent to 
the joint filing on their behalf of this Schedule 13G in connection 
with their beneficial ownership of the Class A Subordinate Voting 
Shares of Gildan Activewear Incorporated at April 30, 1999.

FMR Corp.

By   /s/Eric D. Roiter   			
	Eric D. Roiter
	Duly authorized under Power of Attorney
	dated December 30, 1997, by and on behalf
	of FMR Corp. and its direct and indirect 
	subsidiaries

Edward C. Johnson 3d

By   /s/Eric D. Roiter   			
	Eric D. Roiter
	Duly authorized under Power of Attorney
	dated December 30, 1997, by and on behalf
	of Edward C. Johnson 3d

Abigail P. Johnson

By   /s/Eric D. Roiter   			
	Eric D. Roiter
	Duly authorized under Power of Attorney
	dated December 30, 1997, by and on behalf
	of Abigail P. Johnson

Fidelity Management & Research Company

By   /s/Eric D. Roiter   			
	Eric D. Roiter
	V.P. and General Counsel

	Fidelity Canadian Growth Company Fund

By   /s/Eric D. Roiter   			
	Eric D. Roiter
	Secretary