Background: Our aim was to investigate the frequency of elevated liver enzymes and NAFLD in patients with known insulin resistance during 15 years of follow-up. Methods: Subjects with insulin resistance were identified from a population-based prospective cohort study in Sweden, Malm? Diet and Cancer Study, conducted in 1991-1996. Inall, 285 non-diabetic subjects with insulin resistance established by HOMA-IR (homeostasis model assessment) were invited to do the liver function testing and if elevated, they should be further assessed by radiological examination of the liver, anthropometric measures and blood testing. Results: 165 subjects (57.9%) agreed to do the liver function testing. Of these, 25 subjects (15%) had elevated liver enzymes. After exclusion of other diseases, 5 of the remaining 21 subjects (23.8%) had radiological signs of steatosis. Liver steatosis significantly correlated with ALT (alanine aminotransferase) (p = 0.04), HOMA-IR (p = 0.00) and the metabolic syndrome (p = 0.03). 80% of the subjects with NAFLD had either developed type 2 diabetes mellitus or had impaired fasting glucose and 80% fulfilled the WHO-criteria for the metabolic syndrome, which were of significant differences to the group without NAFLD. Conclusion: The risk of developing elevated liver enzymes and NAFLD at long-term follow-up in insulin resistant subjects is not insignificant, but mainly associated with the simultaneous development of impaired fasting glucose, established diabetes mellitus and/ or the metabolic syndrome.