Abstract: Abstract Inequalities in features and severity of ankylosing spondylitis (AS) have been noticed between men and women, suggesting a possible influence of gender on disease phenotypes. Comparing disease features and characterization of gender differences in clinical features and medications could help elucidate the potential influence of gender on the severity of AS in patients. This study aims to assess the influence of gender on disease patterns in Iranian patients with AS. Three hundred and twenty patients diagnosed with primary AS were assessed for demographic variables, clinical manifestations, HLA status, disease severity, functional capacities, quality of life, and treatment status. Sixty-seven women and 253 men were included corresponding to a male to female ratio of 3.78:1. Both groups were similar regarding ethnicity, positive family history, and juvenile onset AS. HLA-B27 was more frequent among males (78.3 vs. 55.2 %; p <0.001). Therewas a higher proportion of female patients with overall enthesitis (p <0.05). Extraarticular manifestations and treatment modalities presented similar frequencies in both genders. No difference in genderassociated diagnostic delays was observed. Female disease was at least as severe as male disease, and in some aspects, females presented with more severe disease. Despite a relatively similar disease profile, we observed a higher rate of enthesitis among women. Together with the equally high rate of disease activity indices in both genders, these findings indicate an overall longer delay to diagnosis in our country. Early detection and specialized care would be of great practical importance. Keywords Ankylosing spondylitis . Clinical features . Drug therapy . Gender . HLA-B27 . Iran