Mercury is a toxic element which is easily absorbed after ingestion or inhalation and deposited mainly in the kidney. The aim of this study was to evaluate the effects of mercury chloride in rats. Female rats, aged 14 weeks, were receiving mercury chloride in oral doses of 0.068, 0.136, and 0.272 mg kg(-1) body weight (b.wt.) for five consecutive days. Three days after the last dose, the animals were killed. The liver and the kidney were dissected and mercury measured using vapour generation atomic absorption spectrometry. The results show a significant increase in mercury mass fraction in the kidney after two higher doses of mercury chloride, while liver mercury burden showed a significant increase only after the highest dose. Blood samples were analysed using the comet assay and supravitally acridine orange stained micronucleus test. Tail length, tail moment and micronucleus frequency were significantly higher in the treated rats than in control rats, regardless of the dose of mercury chloride, while the difference between the treated groups for both comet and micronucleus parameters was not statistically significant.