A light emitting diode (LED) assembly, comprising a metal substrate (1) which is partly covered on one side with a dielectric layer (2) on which an electric circuit (3) is present, and a multitude of LED units (5, 6, 7) each comprising a LED chip, wherein each LED unit is mounted in a gap in said dielectric layer on the metal substrate by a heat conducting adhesive layer (8), wherein electrical conductors (9) connect each LED unit with the electric circuit on the adjacent dielectric layer, and wherein at least two LED units are mounted together in one gap in the dielectric layer.