To describe the influence of ankylosing apondylitis (AS) on sick leave, presenteeism and unpaid work restrictions and to estimate related productivity costs. 142 consecutive and unselected patients with AS under the care of rheumatologists participated in a longitudinal observational study and completed the Health and Labour Questionnaire (HLQ) assessing disease-related sick leave, presenteeism and restrictions in unpaid work over the previous 2 weeks. Logistic regressions explored which explanatory variables were associated with work outcome. Productivity loss was valued in monetary terms. Among 72 patients in paid employment, 12% had sick leave over a period of 2 weeks and 53% experienced an adverse influence of AS on work productivity while at work. Over this period they reported on average of 5.8 h sick leave and 2.4 inefficient working hours, for which they estimated an extra 1.9 h were needed to complete unfinished work. Among all patients (n=137), 71% had experienced restrictions in unpaid work during the previous 2 weeks with 42% needing help for these tasks for an average of 8 h. The annual production costs for the total group were euro1451 (95% CI 425 to 2742) per patient for sick leave, euro967 (95% CI 503 to 1496) to compensate for hours worked inefficiently while at work and euro1930 (95% CI 1404 to 2471) to substitute loss of unpaid work production. Patients with AS not only have substantial sick leave but also experience restrictions while being at work and when performing unpaid tasks. Limitations in physical functioning are strongly associated with work restrictions. Societal costs of formal and informal care are comparable with the costs of sick leave and presenteeism combined.