OBJECTIVE: It remains uncertain whether the increased direct costs of robot-assisted laparoscopic radical prostatectomy (RALP) are outweighed by cost savings due to shorter postoperative hospital care and shorter sick leave. This study compared the length of sick leave after RALP with that after radical retropubic prostatectomy (RRP). MATERIAL AND METHODS: In a cohort study, information on length of sick leave was retrieved for 274 working men undergoing radical prostatectomy (127 RALP and 147 RRP). Data on confounders such as physical workload, average salary, body mass index and disease characteristics were collected from the medical records. Cox regression models were used to compare the treatment groups. RESULTS: The median number of days with sick leave was 11 in the RALP group and 49 in the RRP group. After adjustment for confounders, patients in the RALP group were twice as likely to return to work at any time during follow-up (hazard ratio = 2.13, 95% confidence interval 1.62-2.80). High physical workload, low salary and high tumour grade were more common in the RRP group and associated with longer sick leave. CONCLUSIONS: Patients in the RALP group had shorter postoperative hospital stay and less need for paid sick leave than patients in the RRP group. These data indicate that RALP shortens the convalescence. Part of this difference may, however, be attributable to different selection of patients and different a priori expectations among patients and their doctors. A prospective randomized study is advocated, although blinding is unfeasible.