We have performed ab initio calculations of CaS, CaSe and CaTe in the B1 (NaCl) and B2 (CsCl) phase. For each compound, we report results for the standard cohesive properties (equilibrium lattice parameters, bulk moduli, cohesive energies), for the equation of state and for the phase transition (transition pressure, compression ratio at the phase transition, percentage change of volume in the phase transition). A detailed comparison with recent experimental results is also performed.