Diets high in trans-fats are associated with an increased risk of cardiovascular disease and components of the metabolic syndrome. The influence of these toxic fatty acids on the development of non-alcoholic fatty liver disease (NAFLD) has not been significantly examined. Therefore, we sought to compare the effect of a murine diet high in trans-fat to a standard high-fat diet which is devoid of trans-fats, but high in saturated fats. Male AKR/J mice were fed a calorically identical trans-fat diet or standard high-fat diet for 10 days, 4 weeks and 8 weeks. Serum alanine aminotransferase (ALT), lipid, insulin and leptin levels were determined and the quantitative insulin-sensitivity check index (QUICKI) was calculated as a measure of insulin resistance. Additionally, hepatic triglyceride content and gene expression of several pro-inflammatory genes were assessed. By 8 weeks, trans-fat fed mice exhibited higher ALT values than standard high-fat fed mice (126 +/- 16 versus 71 +/- 7 U/L, p < 0.02) despite similar hepatic triglyceride content at each time point. Trans-fat fed mice also had increased insulin resistance compared to high-fat fed mice at 4 weeks and 8 weeks with significantly higher insulin levels and lower QUICKI values. Additionally, hepatic interleukin-1-beta (IL-1) gene expression was 3.6-fold higher at 4 weeks (p < 0.05) and 5-fold higher at 8 weeks (p < 0.05) in trans-fat fed mice compared to standard high-fat fed mice. Conclusion: Trans-fat feeding results in higher ALT values, increased insulin resistance and elevated IL-1 levels compared to standard high-fat feeding.