We have observed the nephrotic syndrome in more than one sibling in three unrelated hispanic families. The histological lesion in the involved children was either focal segmental glomerulosclerosis or IgM nephropathy evolving into focal sclerosis. Tissue typing revealed the presence of HLA DRw8 in six out of eight patients. The frequency of this antigen in our patients, when compared with its frequency in a group of unrelated normal hispanic children was highly significant (p less than 0.0001). Our study suggests that there may be a genetic predilection towards developing focal segmental glomerulosclerosis.