A new electron paramagnetic resonance spectrum observed in electron‐irradiated InP is analyzed and attributed to the PInantisite defect. The spectrum has an isotropicgvalue of 1.992±0.008 and a central hyperfine coupling of 0.092±0.005 cm−1with a 100%,I= 1/2 nucleus. Irradiation conditions for the observation of PInare described and comparison is made to antisites in GaP and GaAs.