Human albumin infusions are frequently administered to patients with nephrotic syndrome. We reviewed the clinical course of 27 patients with minimal change nephrotic syndrome (MCNS) in which 16 patients were treated with human albumin (group A) and 11 were not (group B). The percent of body weight gain, serum total protein, serum albumin, urine protein excretion and renal function were equivalent in both groups as was the initial dose of corticosteroid and amount of dietary protein intake. The period from the start of corticosteroid therapy to complete remission for group A (73.4 +/- 19.2 days, mean +/- SEM) was significantly longer than that for group B (17.1 +/- 3.6), (p less than 0.05). 10 patients of group B (10/11 = 90.9%) showed complete remission within 20 days from the start of corticosteroid therapy, but more than 20 days were needed for 9 cases (9/16 = 56.3%) of group A. Moreover, significant correlations were observed between the period required for remission and the duration of albumin administration (p less than 0.01) or the total volume of albumin infused (p less than 0.01). Proportion of relapsers within 2 years after discharge was also higher in group A (68.8%) than in group B (9.1%), (p less than 0.01). In conclusion, administration of albumin may delay the response to corticosteroid therapy and induce more frequent relapses after remission, possibly due to more severe glomerular epithelial changes induced by albumin infusion in addition to preexisting glomerular epithelial changes from the MCNS.