Objective: In axial spondyloarthritis (axSpA), mounting evidence shows female patients to experience a higher disease burden. These differences appear to be particularly large in South America. One explanation could be inequity in treatment access between men and women. The objective was to evaluate gender differences in disease burden and work participation, and the potential influence of treatment, in Latin American patients. Methods: A cross sectional online survey among axSpA patients, collecting disease characteristics, treatment, disease burden (BASDAI, BASFI, ASAS Health Index) and work participation (WPAI). Associations between gender and disease burden or work participation were assessed through regression analyses, correcting for treatment. Results: AxSpA was reported by 472 participants (63% women) and disease activity (BASDAI ≥ 4: 83%), ASASHI (≥ moderately impaired: 91%) and work disability (absenteeism: 41%; presenteeism 82%) were high. Biological use was very low (20%), while 34% used opiates. Females had significantly higher BASDAI, ASAS HI, work absenteeism and presenteeism, although were less likely to receive biologics (26% versus 16%, P < 0.01). Gender differences disappeared after correction for treatment. Conclusions: This web survey in Latin American axSpA patients shows a high disease burden and work impairment. The use of biologics is low, while the use of opiates was alarmingly high. Women used significantly less biologics despite reporting a worse disease state and work disability, which could be due to treatment inequity.