Most forms of therapy for the loin-pain/haematuria syndrome are unsuccessful, though nerve-block procedures and renal denervation sometimes provide temporary relief. Three young patients, with pain so severe that they were dependent on narcotics, were treated for this syndrome. All three had been repeatedly admitted to hospital. Loin pain was unilateral in two patients and predominantly so in the third. Renal function, excretion urography, and angiography were normal, but renal biopsy specimens showed deposition of the third component of complement in the renal arterioles. All were treated with renal autotransplantation; the kidney causing pain (or the one causing the most pain) was completely excised and reimplanted in the iliac fossa. Two patients had complete relief of pain and the third almost complete relief, despite recurrence of haematuria in all three. It is too early to determine whether this major procedure is justified in the treatment of the loin-pain/haematuria syndrome, but the early results are encouraging.