BACKGROUND It is known that some patients with clinical, histological, and laboratory features of primary biliary cirrhosis (PBC) lack serum antimitochondrial antibodies (AMAs). In Asian countries, clinical information regarding AMA-negative PBC is still limited. In this report, we reviewed our patients with AMA-negative PBC in order to further understand this disease. METHODS Clinical features of 36 patients with PBC diagnosed by the histopathologic characteristics of the liver at Chung Gung Memorial Hospital-Lin Kou Medical Center from 1985 to 2000 were reviewed. Of them, 15 were negative and 21 were positive for serum AMAs at presentation. Clinical, biochemical, immunological, and histological parameters were compared between these 2 groups. RESULTS There were only a few differences between the AMA-negative and -positive groups. Significantly more asymptomatic patients (p=0.0017) and a higher positive rate of serum antinuclear antibodies (ANA) (p=0.0323) were observed in the AMA-negative group. Otherwise, there were no significant differences with regard to clinical, biochemical, immunological, or histological parameters. Interestingly, 4 of the 15 patients with AMA-negative PBC became AMA positive during 10, 23, 47, and 56 (mean, 34) months of follow-up. CONCLUSIONS The results show that patients with AMA-negative PBC tend to be asymptomatic and ANA positive. Some patients may develop positive AMA during follow-up. Our data imply that AMA-negative PBC might be a variant of AMA-positive PBC, rather than a separate disease.