A slide fastener is provided which comprises a pair of oppositely disposed stringer tapes each carrying along its longitudinal edge a series of uniformly spaced fastener elements. Each of the fastener elements has a pair of openings in the rounded front end face of its coupling end portion, and a pair of lugs on the shoulders of its neck portion. The lugs are complementary in shape to the openings and so disposed as to snugly fit in the corresponding openings of adjacent fastener elements of the companion stringer tape when the fastener elements on the tapes are coupled together.