The magnetic properties of a mixed Ising ferrimagnetic system, in which the two interacting sublattices have spins σ , ( ± 1 / 2 ) and spins S , ( ± 1 , 0 ) in the presence of a random crystal field, have been studied with the mean field approach. The obtained results show the existence of some interesting phenomena, such as the appearance of a new ferrimagnetic phase, namely, partly ferrimagnetic phase ( m σ = 1 2 , m S = − 1 2 ) and consequently the existence of four topologically different types of phase diagrams. Furthermore, compensation behaviour and re-entrant phenomenon are found for appropriate ranges of crystal field. Thermal magnetization behaviour and phase diagrams have been discussed in detail.