The kidneys from 71 stray dogs submitted for euthanasia were examined by fluorescence microscopy (IF) for evidence of immunecomplex glomerulonephritis (GN) and by histology for evidence of renal pathology. Dogs were divided into three groups according to estimated age: less than one year old (A), adult (B) and aged (C). IgG deposits were found in 0/31 dogs in group A, 6/20 in group B and 10/20 in group C. Diffuse proliferative GN was evident in 0/31, 5/19 and 7/15 dogs in group A, B and C respectively. One dog in group B and two in group C had histological signs of membranous nephropathy. No definite correlation between results of IF and clinical findings were noted and in the aged group the correlation between results of IF and histopathology was poor. These results serve to show that GN may be more common in dogs than previously recognized and that pathological changes may be always accompanied by clinical nephritis.