The potential application of fine-needle aspiration liver biopsy in the documentation of hepatic iron overload has been assessed in iron-loaded rats. Fineneedle aspiration and standard liver biopsy specimens were obtained from three groups of animals supplemented with oral and parenteral iron for 2 to 6 mo. The mean dry weights of standard and fine-needle biopsy specimens were 7.41 ± 0.77 (± S.E.M.) and 0.57 ± 0.54 mg, respectively. Hepatic iron in fine-needle aspiration biopsy specimens correlated significantly with hepatic iron in standard liver biopsy specimens as measured by biochemical determination, computerized image analysis and histological grading (r > 0.9, p < 0.001). In conclusion, we have shown that fine-needle aspiration biopsy of the liver can obtain sufficient tissue for biochemical measurement of the hepatic iron concentration in an animal model of iron overload. The clinical applications of fine-needle aspiration liver biopsy in human beings with iron overload is currently being investigated