Background: chronic lymphocytic leukemia (CLL) patients have a high risk of occurrence of secondary cancers. This risk is three times higher for all cancers and eight times higher for skin cancer. The coexistence of CLL and adenocarcinoma of the prostate is rare.Case presentation: We report a case of 66-year-old man who underwent radical prostatectomy for prostate carcinoma. The final histopathological diagnosis of Gleason 7 adenocarcinoma of the prostate with incidental chronic lymphocytic leukemia (CLL) was made. No further investigations or treatment was offered due to the age, low grade and the stage of the disease. At last follow-up of 12 months, the patient is alive, without disease progression for both lymphoma and prostate with PSA value of 0.1 ng/ml.Conclusion: Early detection of lymphoma after radical prostatectomy will allow optimal management. The analysis of this link requires therefore additional investigations.