Introduction: Prostatic cancer (PC) is one of the most prevalent cancers among men. Early detection is critical because it is only treatable at an early stage. Aim: The current study aimed to evaluate Ki-67’s diagnostic and prognostic value in prostate lesions, as well as the relationship between Gleason’s grade and the degree of Ki-67 expression in PC patients. Materials and methods: The present retrospective study was conducted on 109 prostatic biopsies. The paraffin blocks of these prostatic biopsies were retrieved, reprocessed, and re-examined microscopically for various prostatic pathologies. Ki-67 immunohistochemistry staining was performed in all instances. Only cases diagnosed with PC underwent Gleason's grading. The link between Gleason's grade and the degree of Ki-67 expression was analyzed using a Spearman rank correlation analysis. Results: Ki-67 expression was found to be negative in 82.61% of BPH cases and positive in 93.55% of PC cases.In 61.54% of well-differentiated PC cases and 58.33% of poorly differentiated PC cases, low positive Ki-67 expression (≤10%) and moderately positive Ki-67 expression (11–30%) were found, respectively.There were no cases with Ki-67 expression of >30% in well-differentiated PC; however, 16.67% of poorly differentiated PC cases had extremely positive Ki-67 expression. Conclusion: Ki-67 expression was considerably higher in malignant prostate lesions compared to benign lesions, indicating that Ki-67 as a proliferating marker may be effective in distinguishing PC from BPH.Ki-67 expression was shown to be significantly higher in tumors with a higher Gleason's grade, highlighting its crucial role in the prognosis of PC.