The crystal field parameters (CFPs) of Mn^(2+) in Diglycine calcium chloride tetrahydrate (DGCCT) are calculated using the superposition model. The zero field splitting parameters (ZFSPs) D and E are then evaluated using perturbation and microscopic spin Hamiltonian (SH) theory. The calculated second-rank axial and rhombic ZFSPs are compared with the experimental ones. Both the ZFSPs D and E evaluated theoretically are in good agreement with the experimental values obtained by electron paramagnetic resonance. The results suggest that the Mn^(2+) ion occupies the Ca^(2+) substitutional site in DGCCT.