Pirprofen (Rengasi1)® is one of the recent nonsteroidal anti-inflammatory antirheumatic drugs of propionic acid derivative. This study was carried out on female mice for 19 days using three different doses, to evaluate the cytogenetic and haematological effects of piroprofen on chromosomesand blood picture to get a conclusion about its side effects. At dose levelsof 90 & 112.5 mg.kg.b.wt pirprofen did not induce any significant increase in chromosom abberrations. However after treatment with 450 mg/Kg. was a significant increase in chromosomal aberrations found.