A retrospective 9-year cohort study was conducted to identify the hospitalization costs, length of hospital stay, and mortality associated with nephrotoxicity (NT) among 494 inpatients who were treated with conventional amphotericin B (CAB). Survival regression methods were used to model the effect of NT. The rate of NT was 12%; the overall in-hospital mortality rate was 22%. After adjustment for confounding, NT was associated with a 2.7-fold higher risk of death (P<.001). Although the unadjusted effects of NT on length of hospital stay and hospitalization costs after the initiation of CAB were consistent with small increases, such effects were not significant in multivariate models (time ratio, 1.2 [P=.2]; cost ratio, 1.1 [P=.8]). The greater the number of days before the onset of NT that were included in the analysis, the greater the apparent effect of NT on costs. CAB-associated NT was associated with increased mortality, but it did not impact the costs and length of hospital stay.