C3 glomerulopathy is an heterogeneous group of glomerular diseases associated with acquired or genetic abnormalities of complement alternative pathway (AP) components. It is characterized by predominant C3 deposits in the mesangium and along the glomerular basement membrane (GBM). Presenting features comprise proteinuria (sometimes with nephritic syndrome), haematuria, hypertension and renal failure. C3 glomerulopathy have a poor renal prognosis with progression to end stage renal disease (ESRD) in 50% of cases during the first decade after initial presentation. Moreover, C3 deposits recur in most of cases after renal transplantation. Patients frequently have low serum C3 level attributed to the activation of the alternative pathway of complement. Animal models have confirmed the role of excessive C3 activation in the pathogenesis of C3 glomerulopathy. To date, the optimal treatment remains unknown. It is currently based on the use of angiotensin-converting-enzyme inhibitors (ACEI) and angiotensin II-receptor blockers (ARB), sometimes associated with immunosuppressive therapy. Blockade of C5a release with eculizumab, a monoclonal anti-C5 antibody, may be of particular interest in the treatment of C3G.