Glomerulonephritis is an important cause of end-stage renal disease. Crescentic glomerulonephritis is the most severe form of glomerulonephritis and, if untreated, patients will develop renal failure within days or weeks of diagnosis. Current immunotherapy consists of corticosteroids, cytotoxic drugs and plasma exchange. Challenges include minimising toxicity of therapy, preventing relapse in antineutrophil cytoplasmic antibodies-associated vasculitis and finding an effective treatment for crescentic IgA nephropathy. There are opportunities for more specific therapies using monoclonal antibodies to T cells (and their co-stimulatory receptors), B cells and cytokines, or pharmacological inhibitors of signal transduction. Their efficacy and safety remain to be established with controlled clinical trials. Recent development of urinary cytokine measurement provides a noninvasive biomarker of renal disease activity, which is useful in monitoring response to therapy and assessing prognosis.