We have studied the effects of N incorporation in Ga(In)P and explored their applications for light-emitting diodes (LEDs). The GaInNP epilayers were grown on (1 0 0) GaP substrates by gas-source MBE using an RF nitrogen radical beam source. Red LEDs based on GaN0.011 P-0.989/GaP double-heterostructure grown on (1 0 0) Gap substrates were successfully fabricated. Compared to conventional AlGaInP LEDs, this LED eliminates etching of the GaAs substrate and wafer-bonding of a transparent GaP substrate. Partially relaxed GaN0.011P0.989 active layers, however, degraded the emission efficiency. Incorporation of In in GaN0.015P0.985 alloy to lattice-match to GaP not only maintains the direct band gap. but also improves the sample structural quality and increases the integrated PL intensity by 40%, compared to GaN0.015P0.985.