Doxorubicin, a benzanthroquinone anticancer agent, was examined for its effect on micronucleus induction in cultured human lymphocytes. A statistically significant dose-dependent increase in micronucleus frequency (P<0.001) in binucleated cells was seen and an increase in the kinetochore-positive (P<0.001) and kinetochore-negative micronuclei (P<0.001) was observed. An increase was also observed in the number of necrotic cells, but the frequency of apoptotic cells remained almost constant. This confirms that doxorubicin is both clastogenic and aneugenic.