a fluid-tight slide fastener stringer (10) comprising a support tape (11) made of a fluid-tight soft material, and a row of discrete coupling elements (17) mounted on the tape (11) along an inner longitudinal edge portion (12) thereof. Such tape margin is folded so as to provide therealong a contact portion (13) engageable with a corresponding contact portion (13') of a like companion stringer (10') to effect a fluid-tightness between the two stringers (10,10'). In order to absorb or reduce undue stress exerted on the individual coupling elements (17), each coupling element (17) has a slot (21) extending parallel to the general plane of the stringer (10) transversely through the whole width of a coupling head portion (19) and also extending longitudinally of the same coupling element (17) through the coupling head portion (19) into a base portion (18).