Biochemical and histopathological parameters of the hepatic function were used to quantify the hepatotoxic effects of atrazine in female pigs (gilts) undergoing intensive breeding. Female pigs (cross-bred Swedish and German landrace) received 2 mg atrazine kg-1 body wt. in feed daily during 19 days of the oestrous cycle. The last treatment day corresponded to day -3 of the onset of the next expected oestrus. Blood samples were collected three times daily at 3-h intervals on the first four post-treatment days. Serum activities of gamma-glutamyltransferase (GGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (AP) were determined. Serum activity of GGT was significantly increased throughout the four post-treatment days. In comparison with the control values, a slight but not significant decrease was observed in the serum activities of ALT, AST and AP. Histopathological examination of the liver of exposed pigs showed mild centrolobular parenchymatous degeneration. Interstitial connective tissue proliferation resulted in narrow and irregular bile canaliculi.