GaP crystals were irradiated uniformly on their flat surfaces by 10 MeV-electrons. The “below-gap” absorption coefficient δαb(hv) and the normalized white-light optical densityD/din these samples increased linearly with a dose φ as δαb(2.0) = 3.3 × 10–16 φ andD/d= 1.42 × 10–16φ. The free electron densitynin the conduction band estimated from the X1→X3 absorption band decreased with φ, and as the decrease in the free electron density δnis equivalent to the density of introduced defectsNit could be expressed thatN=δn =Rcφ where the value of the carrier removal rateRc was 5.8 cm-1 for the S-doped sample. These expressions lead to the basic relation thatNis proportional toD/das expressed inN=4.1 × 1016D/d.