Approximately 14% of the working-age Swedish population are either on long-term sick leave or early retirement due to disability. Substantial increase of sick listing, reports of work disabilities and early retirement due to stress and musculoskeletal chronic pain suggest a need for methods of preventing loss of function resulting from these conditions. The present preliminary investigation examined the effects of a brief Acceptance and Commitment Therapy (ACT) intervention for the treatment of public health sector workers who showed chronic stress/pain and were at risk for high sick leave utilization. ACT was compared in an additive treatment design with medical treatment as usual (MTAU). A group of 19 participants were randomly distributed into 2 groups. Both conditions received MTAU. The ACT condition received four 1-hour weekly sessions of ACT in addition to MTAU. At post and 6-month follow-up, ACT participants showed fewer sick days and used fewer medical treatment resources than those in the MTAU condition. No significant differences were found in levels of pain, stress, or quality of life. Improvements in sick leave and medical utilization could not be accounted for by remission of stress and pain in the ACT group as no between-group differences were found for stress or pain symptoms.