OBJECTIVES: This study attempted to identify predictors of sick leave and reduced productivity at work among persons with early inflammatory joint conditions. METHODS: In a prospective cohort study of 210 workers with inflammatory joint conditions present for less than 12 months, data were collected by a medical examination and questionnaires at baseline and after 6 and 12 months. The outcomes were sick leave and reduced productivity at work. Generalized estimation equations (6-month time-lag model) were used to study predictors. RESULTS: Sick leave was predicted by high levels of pain [odds ratio (OR) 3.2], poor physical functioning (OR 4.4), and frequent manual materials handling (OR 2.0), whereas supervisors had a lower likelihood of sick leave (OR 0.2). The predictors of reduced productivity at work were intermediate levels of pain (OR 3.1), poor physical functioning (OR 2.8), poor mental health (OR 2.1), and low support from colleagues (OR 2.2), whereas the workers classified as having nonrheumatoid arthritis were less likely to report reduced productivity than those with inflammatory joint complaints without clinical synovitis (OR 0.4). CONCLUSIONS: Among the workers with early inflammatory joint conditions, self-reported pain and physical functioning affected performance at work, together with manual materials handling and lack of support from colleagues. Early treatment should target pain and physical functioning, and job interventions should aim at reducing physical workload and increasing coworker support.