The clinical characteristics of 118 patients (60 male) with acute renal failure (ARF) admitted between 1980 and 1991, were retrospectively analyzed and compared with our earlier series of the 1960s. The mean age was 53 years (16-82 years). There was a marked decline in the hypotension-related cases (43% vs. 17%, p < 0.01) and a concomitant increase in the nephrotoxic cases (5% vs. 17%, p < 0.005) in recent years. The number of ARF cases significantly decreased after 1986 (31%) compared to the pre-1986 era (69%, p < 0.001). A complete (35%) or partial recovery (55%) was the rule in the majority of the patients. The overall mortality was 27%, virtually unchanged in comparison to the 1960s (30%). However, a tendency toward lower mortality was seen after 1986 (17%) in comparison to before (32%, p < 0.05). Sepsis and cardiovascular complications were the leading causes of death. Fewer deaths were observed among younger patients (< 30 years, 12.5%) compared to middle-aged patients (30-59 years, 34%, p < 0.05) and to these older than 60s (53.5%, p < 0.002). Also, deaths were rare in patients with only renal involvement (6%), increasing to 30% when 2 vital organ systems were affected (p < 0.005) and to 67% in cases with multiple organ failure (p < 0.001). Early institution of dialysis and the nonoliguric forms of the syndrome seem to be associated with better prognosis. In conclusion, the incidence of ARF has declined in recent years, with a concomitant tendency towards lower mortality. Death rate is mainly determined by the age and the number of organ involvement. Early dialysis seems to contribute to the lower mortality seen in recent cases.