Abstract Electron Paramagnetic Resonance (EPR) and optical absorption spectra of Cr 3+ ions doped in single crystals of zinc maleate tetrahydrate (ZMTH) have been studied at room temperature (300 K). The EPR spectra exhibit a group of three fine structure transitions, characteristic of the Cr 3+ ion. From the observed EPR spectra, the spin-Hamiltonian and zero-field splitting parameters have been determined. The optical absorption spectrum exhibits two broad bands characteristic of Cr 3+ ions in octahedral symmetry. From the observed spectrum, the crystal field parameters have been evaluated.