This paper discusses the utilization of MDC and DRG for the evaluation of the activities of surgical divisions. Discharge data on 1901 admissions of the second semester 1992 (97.1% of admissions) to three surgical divisions of ULSS 13 in Veneto Region were assigned to HCFA-DRG, 6th version: 423 (22.3%) in division A; 681 (35.8%) in B; 797 (41.9%) in C. MDC 6 (Diseases and Disorders of the Digestive System) was the most frequent MDC in every division; MDC 4 (Diseases and Disorders of the Respiratory System) had an high proportion only in division A, showing the peculiar feature of this division that effects the thoracic surgery of the whole ULSS. Division A had the highest proportion (56.3%) of admissions for surgical DRGs; division C the lowest (35.4%). DRG 119 (Vein Ligation and stripping) was the most frequent surgical DRG in every division: in the whole sample its DRG specific pre-surgical average length of stay was 1.7 days, and the total average length of stay was 4.7 days. MDC and DRG were usefull in describing case-mix, but it is fundamental to have an appropriate knowledge of these instruments, to avoid in reaching inappropriate considerations, because it was inappropriate the use of the same instruments.