Measles virus (MeV) research is largely dependent on the B95a cell line, which is derived from marmoset B lymphocytes. As this cell line is persistently infected with Epstein-Barr virus (EBV), a novel cell line, COBL-a, was established from human umbilical cord blood. COBL-a cells have a significant advantage over B95a cells because they are of human origin, are free from EBV and have higher sensitivity to wild-type MeV. Thus, COBL-a cells should prove very valuable for both epidemiological and basic studies of MeV.