We have studiedthe copper and metallothionein (MT) in culture skin fibroblasts of patients and hetcrozygotes with Wilson's disease (WD) and ocntrols (5 cascs cach) after incubation in mediums cnataining various concentrations of copper (C1: 15.74μmol./L, C2; 78.70μmol/L, C3: 157.38μmol/L, C4: 314.76μmol/L). Tje results are as follows: 1. In each of the three groups, the copper/protein ratio (Cu/P) in cytosols of 1-5 passages is significantly higher than that of 6-10, 11-15, 16-20 passages. There are no significant differences among 6-10, 11-15 and 16-20 passges. 2. In standard medium, Cu/P in cytosols of three groups are not singificantly different, but Cu/P of patients is significantly higher than that of the other two group after incubation in C4 medium for 12 or hours. 3 After incubation in C1, C2, C3 and C4 mediumsrespectively, the Cu/P in cytosols of the three groups only increased in C4 medium with time (within 72 hurs). It is higheri the patient group than the other two groups. 4 In ther three groups, cytosol copper distributed similarly in two peaks after Sephadex G-75 chromatography, wihic are on high molecular weight (HMW) proteins and MT fractions respectively. It remained the same after incubation in various concentrations of copper. The copper content foundin MT fractions in WD patients is much higher than that of controls and heterozygotes. It is even higherafter incubation in varius concentrationsof copper but no changes was found in cntrols and heterozygotes.