Background: The relationship between obesity and prostate cancer aggressiveness is controversial in recent studies, partly because BMI is the only generally applied marker of obesity. Our study aimed at evaluating the correlation of periprostatic fat (PF) on magnatic resonance imaging (MRI) and adipocytokines with prostate cancer aggressiveness. Patients and method: A total of 184 patients who underwent radical retropubic prostatectomy (RRP) were analyzed retrospectively; different fat measurements on MRI slices and levels of adipocytokines were compared with the clinical and pathologic factors using SSPS ver.13.0. Result: The PF rates showed a statistically significant variation (p=0.019, 0.025) among groups, that is to say, more adipose tissue was distributed in periprostatic areas of high risk patients. Logistic regression analysis adjusted for age revealed a statistically association between the PF, the ratio and the risk of having high-risk disease (p=0.031, 0.024). The levels of IL-6, leptin and c-reactive protein (CRP) significantly increased with the aggressiveness of prostate cancer, and also with PF and its ratio. The strongest correlation was seen between IL-6 and PF (Pearson r coefficient=0.67, P<0.001). No association was observed between adipocytokines and BMI. Conclusion: Periprostatic adiposity not only affects prostate cancer aggressiveness, but also influences the secretion of adipocytokines. IL-6, PF and CRP have promoting effects on progression of prostate cancer.