Background: Prostate cancer (PCa) is one of the most commonly diagnosed cancers in Nigerian men and worldwide. Some comorbidities, such as hypertension, diabetes mellitus, and cardiovascular diseases, have been investigated as potential risks for developing PCa. Hypertension and Type2 diabetes mellitus (DM) are common in the middle-aged and elderly and could be a problem during treatment. Aims and Objectives: This study highlights prostate cancer-associated comorbidities and describes the relationship between Type 2 Diabetes Mellitus and hypertension with prostate cancer among southern Nigerian men. Materials and Methods: This was a 10-year retrospective study on all patients with histologically confirmed prostate cancer at the University of Port Harcourt and two private Urology Hospitals. The case records of the patients were retrieved, and their age, prostate-specific antigen levels, Gleason grade, comorbidities, and treatment received were analyzed. Patients with incomplete data were excluded from the study. The data were collated using Microsoft excel 2020 and analyzed using SPSS Version 20. Results: There were a hundred and fifty-two patients with histologically confirmed PCa. Sixty-four were reported with Gleason scores. Fifty-four (35.5%) of the patients had no associated comorbidity. Hypertension was the commonest associated comorbidity observed in sixty-one (40.1%) patients, followed by Type 2 Diabetes Mellitus in nineteen (12.5%). The poorly differentiated cancers were commonest among the patients with hypertension, Type 2 DM, and patients with both DM and hypertension. There was no association between Type 2 DM, hypertension, and Gleason’s score. Conclusion: Diabetes and hypertension are the most frequent comorbidities associated with Prostate cancer in our patients. There was no statistically significant association between Type 2 DM and hypertension with prostate cancer and Gleason’s score.