This paper explores the trends in industry concentration of the South African manufacturing industry over the period from 1972 - 2001, with a primary focus on developments post 1996. Across all sectors of the manufacturing industry, concentration is found to have decreased. The analysis of bivariate associations yields several results. Amongst others, sectors which are highly concentrated (as measured by the Rosenbluth index) are more likely to exhibit lower employment growth. This is consistent across all ten census years. This paper also provides support for earlier results that low investment rates can in part be attributed to high levels of concentration.