We have fabricated and characterised high-efficiency, long-wavelength PIN photodiodes on In//0//. //5//3Ga//0//. //4//7As/InP/GaAs wafers grown by metal organic vapour phase epitaxy. Initial measurements indicate that good quality devices can be made in this highly stressed material system (lattice mismatch approximately 3. 8%). These results suggest the possibility of fabricating optoelectronic integrated circuits (OEICs) by combining InGaAs(P) electro-optic devices with high-speed GaAs electronics.