Ion Irradiation is a technologically important technique to modify the surfaces. We have investigated the patterning of InP(lll) surfaces by low energy (3 keV) as well as high energy (1.5 Mev) ion beams. After low energy ion irradiation, surfaces exhibit well defined nano dots which ripen at initial stages but exhibit fragmentations at high fluences. The surface rms, at both the energies, displays a similar behaviour of initially increasing with increasing fluences but decreasing for higher fluences. The studies show some common features at these low and high energies, like the smoothening of surface beyond the a/c transition. © 2009, DESIDOC.