Background: Diastolic left ventricular (LV) dysfunction appears more prevalent in ankylosing spondylitis (AS). The effects of tumor necrosis factor alpha (TNF-α) blocking therapy, a strong and effective anti-inflammatory drug, on diastolic LV function in AS are unknown. The objective of the study was to find the effects of 1-year treatment with golimumab 50 mg subcutaneously once per month on systolic and diastolic LV dysfunction in AS patients. Methods: Forty consecutive AS patients were treated with TNF-α blocking therapy for 1 year. Transthoracic echocardiography was performed in all patients at baseline and after 1 year of treatment. Results: Diastolic LV function improved after treatment in four out of six (67%) AS patients who completed follow-up (P=0.125), and did not develop or worsen in any of the other patients. Treatment with TNF-α blocking therapy had no effect on systolic LV function. Conclusion: These findings give support to the hypothesis that diastolic LV dysfunction improves during treatment with TNF-α blocking therapy.