Abstract: A stab-type coupling and method for connecting an end portion of a smooth wall non-metallic pipe or tube to fittings or other pipes or tubes. The coupling is defined by a non-metallic coupling body, a generally elongated hollow insert, an annular retaining spacer ring, seal rings, a collet back-up ring, and a retaining collet all disposed within the recess of the coupling body. The retaining collet is provided with a tapered external surface complementary to an internal frusto-conical surface defined by the back-up ring which in the preferred embodiment is molded within the coupling body. A separate non-metallic chamfer ring which is closely slidably receivable on the hollow insert is also provided. The coupling is made up as by inserting the chamfer ring onto the hollow insert to a position spaced inwardly from the insert outer end and outwardly adjacent to the coupling body.