In this study, urinary cyclophosphamide (CP) excretion rate, as well as micronuclei (MN) in peripheral lymphocytes and in buccal epithelial cells were determined for 26 nurses handling antineoplastics and 14 referents matched for age and sex. In urine samples of 20 out of 25 exposed nurses CP excretion rate was found in a range of 0.02-9.14 mu g CP/24 h. Our results of the analyses of CP in urine demonstrates that when the nurses were handling CP (and other antineoplastic drugs) this particular compound was observed in urine. The mean values (+/-SD) of MN frequencies (%) in peripheral lymphocytes from the nurses and controls were 0.61 (+/- 0.32) and 0.28 (+/- 0.16), respectively (p < 0.01). The mean value (+/- SD) of MN frequency (%) in buccal epithelial cells of nurses was 0.16 (+/- 0.19) and also mean MN frequency in buccal epithelial cells for controls was found to be as 0.08 (+/- 0.08), (p > 0.05). Age, sex and smoking habits have not influenced the parameters analyzed in this study. Handling time of antineoplastics, use of protective equipment and handling frequency of drugs have no effect on urinary and cytogenetic parameters analyzed. No correlation was found between the urinary CP excretion and the cytogenetic findings in nurses. Neither could we find any relationship between two cytogenetic endpoints. Our results have identified the possible genotoxic damage of oncology nurses related to occupational exposure to at least one antineoplastic agent, which is used as a marker for drug handling. As a whole, there is concern that the present handling practices of antineoplastic drugs used in the several hospitals in Ankara will not be sufficient to prevent exposure. (C) 1999 Elsevier Science B.V. All rights reserved.