The analysis of small area variation (SAV) is useful to correlate hospital utilization rates with supply. In this paper the SAV techniques are applied to 26 areas of Catalonia, whose population is covered by the same hospital or group of hospitals in more than 75% of occasions, and hospitalization rates for several surgical procedures (appendectomy, herniorraphy, cholecystectomy, prostatectomy, hysterectomy, tonsillectomy and lens extraction) are analyzed. For these purposes, 26482 discharges recorded in the Minimum Basic Data Set of Hospital Discharges in 1993 were studied. The obtained results show a great variability between areas, which sometimes is larger than the reported in the literature. For amigdalectomy, the ratio between highest and lowest hospitalization rates is 8.8. For prostatectomy and lens extraction the ratios are 4.8 and 4.5, respectively.