Ciprofloxacin is a bactericidal drug which is being used widely throughout the world for the treatment of various bacterial infection. Cytotoxicity and genotoxicity of Ciprofloxacin on human lymphocytes in vitro had been assessed taking various parameters like mitotic index (MI), chromosome aberration (CA), anaphase anomalies, replicative index (RI) and sister chromatid exchange (SCE) as end points. Our results indicate low mitotic index, low replicative index and high frequency of anaphase anomalies on one hand and on other hand, high frequency of chromosome aberration and sister chromatid exchanges (SCEs) in the exposed groups as compared to that of control group. These are the indications of both cytotoxicity and genotoxicity of Ciprofloxacin on human lymphocyte culture in vitro. All the parameters obtained from the experimental group were statistically significant when compared to that of control.