Different facets of hepatitis B infections are encountered in a renal unit. The viral antigens are implicated in the pathogenesis of some cases of glomerulonephritis. Hepatitis B surface (HBS) antigenaemia frequently persists in dialysis patients who contract the virus and presents a significant health hazard to the attendant staff. Persistent HBs antigenaemia does not jeopardise renal allograft survival. The effect of antiHBs antibodies is not clear. Transplantation can reactivate latent hepatitis B infections and render patients HBS antigen (HBSAg)-positive. Hepatic malignancies have been observed and increased patient mortality reported in HBSAg-positive renal allograft recipients. The effect of immunosuppression and maternal viral infection on the fetus is open to speculation.