Background: Prostate cancer is most frequently diagnosed cancer of men and bone is the most common site of metastasis. There is a lack of consensus for the selection criteria for bone scan in low-risk patients. Serum prostate-specific antigen (PSA), which is produced by all types of prostate tissue, is one of the most important biomarkers for detecting prostate cancer, guiding decisions about biopsies of the prostate and offering a way to monitor disease progression. Objective: The aim of this study is to correlate between PSA levels at the time of diagnosis, aggressiveness (Gleason score > 7) and bone metastasis of histologically proved prostate cancer patients. Patients and methods: This study was a Cross Sectional retrospective study collected from medical records at cancer registry archive of Clinical Oncology and Nuclear Medicine at Zagazig University Hospital from January 2014 till January 2019 on 86 prostatic cancer patients with bone metastasis Results: Mean PSA was 217.11±92.56 with range of (100.2 – 502.3), <10 was present in 8.1% of cases, 10-20 was present in 19.8%, 20-100 was present in 34.9% and >100 was present in 37.2% of cases. There was significant relation between PSA and orchidectomy (p<0.001), there was high significant relation between bone metastasis, PSA level (p<0.001) and type of PSA level (p<0.001) and there was significant positive correlation between PSA and GS score, bone metastasis, orchidectomy and ADT. Conclusion: There was strong association between the PSA level, tumor aggressiveness 9 Gleason score), and bone metastasis has been identified in patients already diagnosed as cancer prostate.