Cytogenetic effects of an analgesic antipyretic agent Paracetamol were investigated onin vivobone marrow cells of Swiss albino male mice. The mice were orally administered with 0.625, 1.25 and 2.5 mg of Paracetamol. Chromosomal pictures were prepared 24, 48 and 72 h after the administration of the drug. Chromosomal anomalies such as gaps, breaks, fragments and polyploid nuclei were observed. Structural aberrations were of chromatid type. Frequencies of these anomalies suggest that Paracetamol possess a very weak clastogenic and extremely poor c-mitotic influence in single and cumulative dose series. Cumulative doses appears to be more effective.