Purpose Pain and stress-related ill-health are major causes of long-term disability and sick leave. This study evaluated the effects of a brief psychosocial program, which previously has been tested for an at-risk population of employees. Methods The Effective Communication within the Organization (ECO) program, where supervisors and employees were trained in communication and problem solving, was compared to an active control consisting of psychoeducative lectures (PE) about pain and stress in a cluster randomized controlled trial. First-line supervisors were randomized to ECO or PE, and a total of 191 mainly female employees with self-reported pain and/or stress-related ill-health were included. The hybrid format programs consisted of 2-3 group sessions. Sick leave data was collected from social insurance registers, before and 6-months after the program. Secondary outcomes (work ability, work limitations, pain-disability risk, exhaustion symptoms, perceived stress, perceived health, quality of life, perceived communication and support from supervisors) were assessed at baseline, post intervention, and at 6-months follow-up. Results No effects were observed on primary or secondary outcome variables. Pain symptoms were common (89%), however a lower proportion (30%) were identified as at risk for long-term pain disability, which might explain the lack of evident effects. The Covid-19 pandemic affected participation rates and delivery of intervention. Conclusion In this study, preventive effects of the ECO program were not supported. Altogether, the findings point at the importance of selecting participants for prevention based on screening of psychosocial risk. Further research on workplace communication and support, and impact on employee health is warranted.