Introduction The aim of this study was to investigate the effectiveness of an interactive website aimed at empowerment of disability claimants, prior to the assessment of disability by an insurance physician. Methods A randomized controlled trial was conducted. Claimants applying for a work disability pension after being sick-listed for 104 weeks, were randomized into either an intervention group or control group. Participants who were randomized into the intervention group were able to logon to the website www.wiagesprek.nl, which mainly consisted of five interactive modules aimed at increasing knowledge, self-awareness, expectations, self-efficacy, and active participation. Participants from the control group were directed to a ‘sham’ website with commonly available information only. The primary outcome was empowerment. Secondary outcomes included coping, knowledge, claimant satisfaction, perceived justice, and physician satisfaction. Outcomes were assessed at baseline, 2 days before the disability assessment, as well as 1 day after, 6 weeks, and 4 months after the disability assessment. Results Claimants were randomly assigned to the intervention group (n = 123) or a control group (n = 119). The intervention had no significant short- and long-term effects on empowerment, but the intervention increased claimants’ knowledge significantly compared to the control group. Claimant satisfaction with the disability assessment interview and claimant perceived justice on the outcome of the assessment were lower in the intervention group (statistically not significant). Furthermore, the intervention had a significant negative effect on claimants perceived procedural justice. Conclusion Although knowledge increased significantly, the intervention www.wiagesprek.nl was not successful in reaching its primary target, that is, to increase levels of empowerment among disability claimants, prior to the assessment of disability.