For several years we carried out a follow-up of two patients with IgA mesangial glomerulonephritis with antecedents of exposure to toxic substances (cadmium and organic solvents). The first case involved a 47 year old male who was diagnosed with mesangial IgA glomerulonephritis eight years ago; he had been working for twelve years as a solderer. He had used metal bars containing 25% cadmium as part of the soldering material. Very high levels of cadmium were detected in his blood and urine. The second case involved a 50 year male who was exposed to a wide number of organic dissolvents for 23 years. Three years ago he was diagnosed with a proliferative diffuse mesangial glomerulonephritis with IgA deposits; in spite of that, the patient continued working until one year ago, when was found to have a chronic stage 3 renal disease secondary to IgA nephropathy. Patients diagnosed with mesangial IgA glomerulonephritis should be kept apart from exposure to nephrotoxic substances.