The objective of this study was to investigate the effects of prostate cancer (PCA) surgery on the stress system and to identify potential independent factors associating with stress recovery. The design of the study was prospective and PCA surgery included robot-assisted radical prostatectomy (RARP) or retro pubic radical prostatectomy. Between February and December 2013, 151 consecutive patients were evaluated. The effects of PCA surgery on the stress system were measured by cortisol serum levels before and after surgery on post-operative day (POD) 0, 1, 3, 5 and 45. Statistical methods were applied. RARP was performed in 71% of cases. PCA surgery triggered the stress system which immediately (POD 0) responded by cortisol overproduction which induced the negative feedback mechanism that started on POD 1, continued on POD.