To examine inter-spouse transmission as one of the potential routes of infection for hepatitis C virus (HCV), 121 patients with HCV-related chronic liver disease who tested positive for antibodies to HCV (anti-HCV) and their spouses were studied.

Of these, 21 (17.4%) patients had spouses with anti-HCV.

In 12 couples, the HCV genotype matched (type II : 10 couples, type III : two couples).

The genotype differed in six couples.

One patient was positive for anti-HCV, but negative for HCV-RNA, while the spouse was positive for both.

The remaining two couples were only positive for anti-HCV.

Genetic heterogeneity in the hypervariable region 1 of HCV was analysed in 11 couples with matched genotypes.

In two couples, no mutation was recognized in the putative E2/NSI genes using the heteroduplex method.

The present study provides evidence to verify household transmission of HCV between patients and their spouses.

These results suggest that inter-spouse transmission may be a potential route of transmission of HCV infection.

However, other environmental factors (e.g. the duration of the marriage) cannot be ignored.