In an earlier paper (House, 1973) the structural characteristics of manufacturing industries, as indicated by the number of competitors in relation to the size of the market, were related to their performance in Kenya for 1963. The index of concentration was constructed so that account was taken of the influence of foreign competition in the home market. This factor is relatively large in some markets of a developing country and could not be ignored as it has been in most other studies of the developed world. The results showed both a positive and continuous relationship between a measure of performance and the index of concentration. In addition, it proved impossible to establish any independent influence on performance of a proxy measure for the capital requirements barrier to entry, which has been found to be important in other studies (Bain, 1951; Mann, 1966).