This paper reports an analysis of the determinants of the level and changes in Polish industrial concentration in the early post-transition era. In particular, the relative effects of foreign and state ownership are examined. The empirical evidence is based on a panel of 144 Polish manufacturing industries over the period 1989–1993. The results suggest that both state and foreign ownership have a significant impact on industry concentration and this relationship is U-shaped. Minimum efficient scale is found to be the only other factor to impact on industry concentration. Copyright Springer Science+Business Media, LLC 2005Post-transition, Foreign direct investment, State ownership, Industry concentration, L11, F23,