Susceptibility to primary biliary cirrhosis (PBC) may be partly inherited although instances of PBC within families are only infrequently described. The records of 736 patients with PBC seen over a 25 year period were examined to identify those with a positive family history. Ten patients originating from eight families were identified, giving a frequency of 1.33%. They comprised mother and daughter pairs; in two families both mother and daughter had been seen at our clinic. The daughters presented at an earlier age, median 36 years (range 24-54), than the mothers, 52 years (50-81). During follow up one daughter (45 years) and six mothers have died (range 53-81 years) and two mothers and one daughter have had a transplant aged 57, 57, and 30 years respectively. It is concluded that familial PBC is not rare, that it is related to maternally inherited factors, and that disease tends to present earlier in the second generation.