We have grown by organometallic vapor phase epitaxy high-purity InP on Si substrates using a GaAs intermediate layer. The InP layers exhibit residual electron concentration as low as 5 x 10(14) cm-3 and electron mobilities as high as 4000 and 25 000 cm2/V s at 300 and 77 K, respectively. The achieved InP quality is dependent on the GaAs intermediate layer thickness. These excellent electrical properties are due to high crystal qualities as evidenced by x-ray rocking curve half width as low as 215 arcsec and defect densities on the order 10(8) cm-2. p/n junctions, with ideality factors as low as 1.6 and low leakage currents, confirm the device quality of this material.