The ability of cumene to induce micronuclei in bone marrow polychromatic erythrocytes of groups of 10 male and 10 female Crl:CDR-1(ICR)BR Swiss mice was evaluated at dose levels of 0.25, 0.50, 1.00 (2 doses), and 1.00 (1 dose, 15 animals) g/kg administered in paraffin oil by gavage once daily for two days using bone smears prepared, half on day 3 and half on day 4, following onset of dosing. Dose levels were based on prelim- inary toxicity studies. No significant (p<=0.05) increase occurred in any cumene dose group relative to controls, although the positive control, admin- istered 75 mg/kg cyclophosphamide intraperitoneally, didshow a difference (p<=0.05).