The aim of this study is to define outcome predictors that might influence the prognosis and the mortality rate either of percutaneous drainage (DP) or open surgical drainage (DC) for abdominal abscesses. Seventy-one patients with 81 intra-abdominal abscesses were prospectively studied. They were 40 males and 31 females. Mean age was 47 +/- 15 years. Thirty-six (50.7%) patients had a simple abscess, while 35 (49.2%) had a complex abscess. Abscesses occurred most commonly in the sub-hepatic area, pelvic and para-colic space. Thirty-two (45%) patients had a percutaneous drainage, while 39 (54.9%) underwent an operative drainage management. Criteria for treatment selection were not randomized. However the two groups were statistically similar in respect to clinical features, cirrhosis, nutritional status, APACHE II scores), genesis and characteristics (simple, complex) of the abscesses. The treatment was considered successful when not requiring further drainage and the patient survived. Abdominal abscesses were cured in 53 (74.6) patients. In 13 cases (18.3%) a further drainage was necessary to obtain a complex resolution. Post drainage complications were significantly higher in the surgical drainage group (38.4% vs 12%, p < 0.05) because of the high incidence of wound infections. The overall mortality rate was 7%. Using an univariate analysis model, the only significant variable related to unsuccessful outcome in both the percutaneous and surgical group was abscess complexity (p < 0.005). Elderly (p < 0.005), malnutrition (p < 0.03), presence of cancer (p < 0.05), a high APACHE II score (p < 0.005) and the presence of a complex abscess (p < 0.02) were significantly identified as determinants of death.