Résumé : Prostatic intraepithelial neoplasia (PIN) fulfils the majority of requirements for a premalignant change in the human prostate. Forty-eight patients were diagnosed to have high grade PIN on prostatic needle biopsy. During a follow-up period, 23 (47.9%) were found to have adenocarcinoma on subsequent biopsies. We compared the patients age, the digital examination, the transrectal ultrasound appearance (TRUS) and the serum PSA level between those in whom cancer was detected subsequently and those with PIN alone. There was a statistically significant difference in the transrectal ultrasound appearance (TRUS) and the serum PSA level between the two groups (p < 0.001, p < 0.016 respectively). In conclusion, patients with high grade PIN, elevated serum PSA with hypoechoic zone on TRUS should be rebiopsied 3 months after the initial diagnosis. If the results are negative, close follow-up is mandatory.