In April 2000 the Irish government introduced a national minimum wage of IR£4.40 (€5.58) an hour. We use data from a specifically designed survey of firms to estimate the employment effects of this change. Employment growth among firms with low-wage workers prior to the legislation was no different from that of firms not affected by the legislation. A more refined measure of the minimum wage, however, suggests that the legislation may have had a negative effect on employment for the small number of firms most severely affected by the legislation. However, the size of these effects is relatively modest. © 2006 The Authors; Journal compilation © 2006 CEIS, Fondazione Giacomo Brodolini and Blackwell Publishing Ltd.