Light-emitting diode fixture, comprising: a housing with a base having a planar supporting surface comprising a flat dielectrical light-emitting diode-carrier substrate of the type having a top side provided with both contact tabs and light-emitting diodes and an underside provided with a heat-dissipating heat sink, a light-emitting diode holder having on an underside a recess in which the light-emitting diode-carrier substrate is retained and a light opening for the light-emitting diode-carrier substrate on a top side, a first pair of contact tabs (9A, 9B) in the recess, a coupling region in one edge portion of the light-emitting diode holder with a second pair of contact tabs (11A, 11B), a connector for an outside power supply of the light-emitting diode-carrier substrate comprising a coupling region in an edge portion with a third pair of contact tabs (17A, 17B), wherein the respective coupling regions of the light-emitting diode holder and the connector are joined together by mating engagement ends in which the second and third pair of contact tabs (11A, 11B; 17A, 17B), respectively, are in current conducting contact, wherein the connector and the light-emitting diode holder each comprises a dielectric body with a central mounting axis (C-C) which forms a normal to the planar supporting surface of the housing, wherein the engagement ends of the light-emitting diode holder and the connector overlap each other in the coupling region with mating edge portions (5A, 3A) characterized in that said edge portions comprise guiding members having mutually interacting guide pins (13, 13) and insert openings (15, 15) oriented parallel to said the mounting axis (C-C), and that the connector and the light-emitting diode holder are mutually pretensioned by fasteners (27, 27; 20, 20) in the direction of the mounting axis (C-C) against the supporting surface and furthermore against the supporting surface with the heat-dissipating heat sink of the light-emitting diode-carrier substrate resting against said supporting surface in combination with a clamping action occurring in the region between said overlapping edge portions (5A, 3A). a housing with a base having a planar supporting surface comprising a flat dielectrical light-emitting diode-carrier substrate of the type having a top side provided with both contact tabs and light-emitting diodes and an underside provided with a heat-dissipating heat sink, a light-emitting diode holder having on an underside a recess in which the light-emitting diode-carrier substrate is retained and a light opening for the light-emitting diode-carrier substrate on a top side, a first pair of contact tabs (9A, 9B) in the recess, a coupling region in one edge portion of the light-emitting diode holder with a second pair of contact tabs (11A, 11B), a connector for an outside power supply of the light-emitting diode-carrier substrate comprising a coupling region in an edge portion with a third pair of contact tabs (17A, 17B), wherein the respective coupling regions of the light-emitting diode holder and the connector are joined together by mating engagement ends in which the second and third pair of contact tabs (11A, 11B; 17A, 17B), respectively, are in current conducting contact, wherein the connector and the light-emitting diode holder each comprises a dielectric body with a central mounting axis (C-C) which forms a normal to the planar supporting surface of the housing, wherein the engagement ends of the light-emitting diode holder and the connector overlap each other in the coupling region with mating edge portions (5A, 3A) characterized in that said edge portions comprise guiding members having mutually interacting guide pins (13, 13) and insert openings (15, 15) oriented parallel to said the mounting axis (C-C), and that the connector and the light-emitting diode holder are mutually pretensioned by fasteners (27, 27; 20, 20) in the direction of the mounting axis (C-C) against the supporting surface and furthermore against the supporting surface with the heat-dissipating heat sink of the light-emitting diode-carrier substrate resting against said supporting surface in combination with a clamping action occurring in the region between said overlapping edge portions (5A, 3A).