A simple, accurate and specific proton magnetic resonance (PMR) procedure is developed for the assay of praziquantel and its tablets. The method involves comparing the integral of the multiplet of praziquantel (positioned at δ 7.3 ppm) to that of the sharp singlet signal (positioned at δ 6.3 ppm) of maleic acid which is used as intenal standard. The method reported in this study gives accurate and reproducible results when applied for the analysis of both authentic drug and its tablets. In addition the PMR spectrum helps in confirming the identity and purity of the drug.