Many children with steroid-dependent nephrotic syndrome (NS) have significant sequelae despite steroid-sparing therapies. Levamisole may reduce short-term relapse frequency (RF) with minimal side effects. Little data exist, however, as to its long-term effect. To assess both short- and long-term efficacy in NS, RF and cumulative annual steroid burden were quantified in ten consecutive children with steroid-dependent NS treated with levamisole. Data were analyzed for three time periods: 1 year prior to levamisole therapy (Pre-Lev), during 1 year of levamisole therapy (During-Lev), and the year after cessation of all levamisole therapy (Off-Lev). Median RF fell from 6.0 (4.0-9.0) relapses/patient per year Pre-Lev to 0.0 (0.0-4.0) During-Lev (p = 0.002) with 6/10 patients having no relapse and 0.5 (0.0-8.0) Off-Lev (p = 0.01) with 5/10 patients without relapse. Concurrently, cumulative annual steroid burden fell from 6,067 (1,660-8,691) mg/m(2) per year Pre-Lev to 2,920 (782-5,271) During-Lev (p = 0.002) and 716 (0-3,637) Off-Lev (p = 0.002). In 4/5 hypertensive children, blood pressure normalized During-Lev. Somatic indices also improved: height Z scores, which fell from 0.8 (-2.4 to 3.6) at diagnosis to -0.6 (-2.7 to 0.4) Pre-Lev (p = 0.004), remained stable at -0.6 (-3.0 to 0.6) after 1 year of therapy and -0.5 (-2.6 to 0.2) Off-Lev. Height velocity improved from 3.0 (0.3-6.0) cm/year Pre-Lev to 3.7 (0.0-8.0) cm/year During-Lev and 5.4 (0.0-9.1) Off-Lev. We conclude that levamisole is an effective short- and long-term steroid-sparing agent in pediatric NS.