The kidney does not usually present specific lesions in cystic fibrosis (CF), although in recent years renal involvement has been reported, particularly amyloidosis and immune complex glomerulonephritis. IgA nephropathy is rare. We report four cases of IgA nephropathy out of five renal biopsies performed in the last three years in patients with CF and renal involvement and discuss the possibility of a relationship between IgA nephropathy and CF.