While infections are known to precipitate disease relapses in childhood nephrotic syndrome, it is unclear whether diarrheal illnesses carry the same risk for relapses as acute respiratory tract infections. This paired case control study included age and sex matched episodes of relapses (cases) and remission (controls). Records were reviewed retrospectively for the presence of acute respiratory tract infections and diarrhea in the two weeks preceding the clinic visit. McNemar test was used to examine associations between these infections and relapse. In 17 patients with 38 paired episodes of relapses and remission, the odds ratio for relapse compared to remission, associated with acute respiratory tract infections, was 3.25 (95% confidence interval: 1.06, 9.97; P = 0.03), while that for acute diarrhea was 3.5 (95% confidence interval: 0.73, 16.85; P = 0.10). Acute respiratory tract infections are a risk factor for relapses in pediatric nephrotic syndrome, while acute diarrhea does not predispose to disease relapses.