Objective: To retrospectively evaluate the effect of anti-tumor necrosis factor-alpha (TNF-α) drugs on hepatic and renal functions in patients with ankylosing spondylitis (AS). Methods: A total of 148 patients (89 male, 59 female) who were followed up for a minimum duration of 1 year on newly started anti TNF-α therapy were included. Patients were divided into 5 groups based on the TNF-α treatment received. Initially, pre-treatment BASDAI (Bath Ankylosing Spondylitis Disease Activity) scores and laboratory results were compared between the groups before the treatment. Also, ESR (erythrocyte sedimentation rate), C-reactive protein (CRP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, and creatinine values were compared before treatment and at 3, 6, and 12 months after treatment. Also presence of hematuria and proteinuria was examined. Results: Of the overall group, 68 (45%), 33 (22%), 23 (15%), 18 (12%), and 6 (4%) received golimumab, certolizumab, etanercept, adalimumab, and infliximab. Baseline demographic characteristics, disease activity scores, and laboratory parameters were comparable between the groups (P > .05). There was a significant decline in BASDAI scores from baseline at 12 months (pre-treatment 5.24 ± 0.5, 3.01 ± 0.48 post-treatment at 12 months, P < .001). Although there was an increase in AST and ALT from baseline to 3, 6, and 12 months of treatment, the values remained within normal range (P > .05). Also, there were no significant changes in mean creatinine levels (P > .05). There were no correlations between disease activity parameters (ESR, CRP, and BASDAI) and hepatic and renal functions (P > .05). Conclusion: No hepatotoxicity or nephrotoxicity were found in association with the use of anti-TNF-α agents over a 1 year period. However, hepatotoxicity and nephrotoxicity are among known adverse effects of these agents. Based on the existing literature data, routine monitoring of patients in terms of potential hepatic and renal toxicity before and after treatment remains a valid recommendation in clinical practice.