Abstract: A plug-in connector for medical tubes is provided with a first plug-in part (10) and a second plug-in part (30), wherein the second plug-in part (30) extends around the first plug-in part (10) in the plugged-together state. The second plug-in part (30) has at least one forwardly protruding snap-in element (32), which has at its front end at least one inwardly protruding projection (34). The inwardly protruding projection is provided for meshing (engaging) with a complementary recess (14) in the outer surface of the first plug-in part (10) in order to thus hold the second plug-in part (30) fixed in the axial direction on the first plug-in part (10) due to the projection (34) meshing with the recess (14).