A prospective, randomized, double blind and placebo-controlled study to evaluate the effectiveness of periprostatic infiltration with lidocaine to reduce pain of prostatic biopsy. In a thirteen months period of time, 115 patients were randomized to receive 10 ml of lidocaine 1% (n=60) or saline (n=55). Evaluating the pain with visual analogue scale (0-10), the first group referred average pain of 3.83 and the second group of 6.87, being this difference clearly significant (p<0.005). There were not complications from anesthesic puncture. The periprostatic infiltration is easy to perform without complications and it is effective in reducing the pain of this procedure. It should be used as a routine procedure in prostatic biopsy.