The full length hepatitis C virus (HCV) core gene was isolated from a Newcastle strain and expressed in E. coll. A truncated HCV core gene which lacks the hydrophobic carboxyl‐terminal sequence was also expressed. The truncated HCV core was expressed at higher levels with fewer cleavage products. Antibody reactivity to the recombinant HCV core antigen was analysed by ELISA and Western blotting in 60 HCV antibody‐positive patients with a broad spectrum of liver disease. There was no significant difference between the presence of IgG to recombinant HCV core and reactivity to the core antigen in the RIBA‐2 test. There was also no significant difference between the presence of IgG to recombinant core and diagnostic PCR as a marker for active liver inflammation. © 1995 Wiley‐Liss, inc.