The aim of our study was to determine the outcome of children with severe Henoch-Schönlein nephritis (HSN) and immunoglobulin A (IgA) nephritis (IgAN) treated with early plasmapheresis alone. Children with acute renal impairment, heavy proteinuria or both and histology greater than grade 3 were treated with early plasmapheresis alone. Glomerular filtration rate (GFR) estimated from plasma creatinine (eGFR), urine albumin:creatinine ratio (UA/UC) and blood pressure 2 weeks after treatment and were measured at the last follow-up. Sixteen children (14 HSN, 2 IgAN) had a mean eGFR of 56 (17-136) ml/min per 1.73 m2 and UA/UC of 590 (12-1,379) mg/mmol. Fifteen were referred at presentation and one after 2 months, and all commenced plasmapheresis within 6 (2-13) days. All had at least nine exchanges of 90 ml/kg over 2 weeks. At 2 weeks, the eGFR had increased by 51 (95% CI 34-68; P=0.002), and the UA/UC fell by 457 (95% CI 241-673; P=0.0001). At last review after 4 (1-7.5) years, the late-referred child had required a renal transplant but the other 15 had normal eGFRs (98-142), did not require hypotensive medication, and had normal or minimally elevated UA/UC (maximum 42). Children with severe HSN and IgAN recover well if treated with plasmapheresis alone without the need for immunosuppressive therapy. A randomised trial is needed.