Autoimmune tubulo-interstitial nephritis was induced in guinea pigs two or three weeks after immunization with the canine tubular or glomerular basement membrane. There was interstitial infiltration of mononuclear cells and formation of multinucleated giant cells associated with a linear deposition of IgG on the renal basement membranes. Seven days after serum transfer from the affected guinea pigs, one of three dogs developed glomerulonephritis and focal tubulo-interstitial lesions with a linear deposition of guinea pig IgG on the tubular and glomerular basement membranes.