Abstract Indium phosphide samples were irradiated with swift (100 MeV) 56Fe 7+ ions with different fluences varying from 5 × 10 12 to 2 × 10 14 ions cm − 2 at room temperature. Atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques have been used to investigate the irradiation effects. Atomic force microscopy observations revealed the presence of hillocks surrounded with valleys in all irradiated samples. The shape, size and height of the hillocks were found to vary with respect to ion fluences. Root mean square surface roughness was found to change from 0.33 nm to 7.49 nm. X-ray diffraction studies revealed increase in the amount of disorder in the irradiated samples as ion fluence increases.