We report high‐brightness blue and green light‐emitting diodes (LEDs) based on II–VI heterostructures grown by molecular beam epitaxy on ZnSe substrates. The devices consist of a 2–3 &mgr;m thick layer ofn‐type ZnSe:Cl, a ∼0.1 &mgr;m thick active region of Zn0.9Cd0.1Se (blue) or ZnTe0.1Se0.9(green), and a 1.0 &mgr;m thickp‐type ZnSe:N layer. The blue LEDs produce 327 &mgr;W (10 mA, 3.2 V), with the light output sharply peaked at 489 nm, and exhibit an external quantum efficiency of 1.3%. The green LEDs produce 1.3 mW (10 mA, 3.2 V) peaked at 512 nm, corresponding to an external quantum efficiency of 5.3%. In terms of photometric units, the luminous performance (luminous efficiency) of the devices is 1.6 lm/W (blue) and 17 lm/W (green), respectively, when operated at 10 mA. ©1995 American Institute of Physics.