The immunohistochemical expressions (IE) of p27(kip1) and Ki-67 (MIB-1), both involved in cell cycle regulation and cell proliferation, and their ability to predict biochemical failure, were assessed in patients with clinically localized prostate cancer who had underdone radical prostatectomy of curative intent. In addition, p27(kip1) and Ki-67 (MIB1) expressions were correlated with several pre-operative and post-operative parameters, such as Gleason score, extracapsular extension, seminal vesicle involvement, pelvic lymph nodes metastasis, positive surgical margins, coexistence of high-grade prostatic intraepithelial neoplasia, tumour size, prostate volume and PSA levels. Our analysis involved 130 consecutive radical prostatectomy specimens. A statistically significant correlation of low p27(kiP1) IE with seminal vesicles involvement, increased tumour volume and high pre-operative PSA values was documented. Low p27(kiP1) IE was significantly correlated with an increased likelihood of biochemical failure after radical prostatectomy. In addition, the increased IE of Ki-67 (MIB1) correlated significantly with metastatic disease in the pelvic lymph nodes and was a significant predictor of biochemical failure. Cox regression analysis, which included p27(kip1) expression, Ki-67 (MIB1) expression and all the pre-operative and post-operative parameters, showed that pelvic lymph node involvement and Ki-67 (MIB1) IE were independent prognostic markers of biochemical failure after radical prostatectomy.