['To retrospectively investigate and compare the effects of tumor necrosis factor alpha inhibitors (TNFi) on hepatic enzymes in ankylosing spondylitis (AS) patients.', "A retrospective analysis of the records of 94 AS (66 male, 28 female) patients using TNFi was performed. Patients' clinical data, Bath Ankylosing Spondylitis Disease Activity (BASDAI) scores, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels were all examined. Liver function test (LFTs) results of patients before the treatment and 3, 6 and 12 months after treatment with TNFi were investigated. Aspartate transaminase (AST) and alanine transaminase (ALT) levels were investigated as indicators of LFTs.", 'The TNFi drugs used were infliximab (n = 28), adalimumab (n = 32) and etanercept (n = 34). Pre-treatment values of ESR, CRP and BASDAI scores were 28.3 ± 20.1 mm/h, 1.5 ± 1.2 ng/dL and 5.2 ± 0.8, respectively. Following TNFi use there was a statistically significant decrease in disease activity score (P = 0.001). There was a significant increase in LFT at the third month evaluation compared to the initial values, while the average value was within normal range (baseline AST 19.6 ± 10.8 U/L, ALT 19.1 ± 6.4 U/L, third month AST 31.3 ± 21.6 U/L, ALT 28.1 ± 18.1 U/L, P = 0.001). Drug group comparison analysis revealed a significant difference in the adalimumab group value at the end of the first year, but no other significant difference in the data for the other months (P > 0.05). No significant correlation was determined between initial disease activity scores and LFT.'] Does treatment of ankylosing spondylitis with TNF inhibitors have adverse effect on results of liver function tests : a longitudinal study?