ABSTRACT PURPOSE: The aim of this study was to evaluate the efficacy of 1.5T MRI using lesion length (LL) and tumor-capsule contact length (TCL) in detecting extraprostatic extension (EPE) in prostate cancer (PCa). MATERIALS and METHODS: A total of 110 patients who underwent radical prostatectomy due to PCa were enrolled. Preoperative MR images of the patients were evaluated retrospectively by two independent observerswho did not know the histopathological results. The observers evaluated LL and TCL. The radiological findings, including lesion location, were verified using histopathological mapping. RESULTS: Multiparametric MR examination of the prostate demonstrated low sensitivity but high specificity, with significant differencesfor detecting EPE (Observer 1, p < 0.0001; Observer 2, p = 0.003). The increased PI-RADS score correlated positively with the increased EPE rate. The LL and TCL demonstrateda statistically significant difference between patients with and without EPE. The TCL was a significant parameter for EPE, with high sensitivity and low specificity for both observers. Cut-off values were obtained for both the LL and TCL. CONCLUSION: The results revealed that 1.5T MRI demonstrated low sensitivity and high specificity in detecting EPE. The LL and TCL may be beneficial indirectly in detecting EPE. Keywords: Prostate Cancer; Capsular Invasion; Extraprostatic Extension; Multiparametric Prostate MR; Tumor-Capsule Contact Length