In this study, we evaluated the effect of low level occupational exposure of nurses in a medical oncology unit in Cairo, Egypt, to anticancer drugs. Twenty nurses who constantly handled these drugs and 20 controls, matched according to age and sex, were examined. Metaphase chromosomes were studied. Percentages of metaphases with chromosomal aberrations were significantly higher (P < 0.001) in the exposed group (6.1 +/- 2.7) versus the controls (2.6 +/- 1.6). The detected chromosomal aberrations were in the form of chromatid gaps, chromatid breaks and acentric fragments. Micronucleated peripheral blood lymphocytes were also analyzed in cytochalasin B treated binucleated lymphocytes. There was significant increase in cells with micronuclei (P < 0.001) in nurses (10.05 +/- 4.71) in comparison to the matched control (5.42 +/- 2.22) (P < 0.001). Nurses exposed to the cytotoxic drugs for > or = 48 months showed a slightly higher frequency of cells with chromosomal aberrations as well as micronucleated cells than those exposed for < 48 months, but these differences were not statistically significant (P > 0.05).