Many patients with chronic pancreatitis (CP), even in the absence of intrinsic renal disease, are found to have abnormal urine, with persistent proteinuria, cylindruria, micro-hematuria and leukocyturia. The kidneys of 12 necropsy cases with CP showed mild to moderate arterial and arteriolar nephrosclerosis and no other significant changes. Renal biopsies were performed in 10 patients with CP without evidence of systemic disease or intrinsic renal disease, but with persistent urinary abnormalities. By light microscopy, mild arterial and arteriolar nephrosclerosis was present in 5 instances. In 1 patient, evidence of the reparative phase of acute tubular necrosis was noted. In 5 biopsies, electron microscopy revealed minimal to mild increase in mesangial matrix. Mild thickening of the glomerular basement membrane (GBM) was found in three instances but there was no clear-cut evidence of diabetic glomerulosclerosis. The presence of subendothelial electron-lucent material in 3 cases suggests the possibility of previous sub-clinical episodes of intravascular coagulation. The most consistent finding was the presence of lipid material in the cytoplasm of glomerular and tubular cells. The renal lesions associated with CP are mild, nonspecific and nonprogressive. Various pathogenetic factors can be invoked to account for their presence and for the urinary abnormalities found in patients with CP.