Generalizing cofinite groups, M.R. Dixon [Glasgow Math. J. 23 (1982)] has shown how a residually Chernikov group can be made into a topological space, which is called a co-Chernikov group. A co-Chernikov group can be embedded in a compact co-Chernikov group, its pro-Chernikov completion. In this paper, we characterize centralby-Chernikov groups as those co-Chernikov CC-groups whose pro-Chernikov completions are again CC-groups.