Uncovering the effects of privatization is difficult, because privatization of a particular firm usually is not an accident. This paper tests the effects of privatization on productive and allocative (market) efficiency using a rich panel data set of 22 privatized cement plants from Turkey in the 1983-99 period. Since, all public cement firms were privatized and we have preand post-privatization data for all, we are able to avoid the problem of endogeneity associated with sample selection. Our analysis goes beyond just examining the privatization effects and explores how privatization really works. Changes in objectives of the firm (ownership effect) and changes in market structure (environment effect) may both be responsible for privatization outcomes. We find that ownership effects are sufficient to achieve improvements in labor productivity. Our results on allocative efficiency, however, are dependent on changes in the competitive environment. While all plants seem to improve labor productivity through works force reductions, plants privatized to foreign buyers also increase their capital and investment significantly. (c) 2006 Elsevier Ltd. All rights reserved.