THIS paper examines the effect of import competition on the profitability of a cross-section of 32 manufacturing industries in the United Kingdom. The research originates from a chapter of the author's doctoral dissertation, completed in I976, and the main results from that are reported in Section II. As a check on robustness, the hypotheses advanced in the dissertation are retested with more recent data (section IV). A more substantial extension of the earlier research concerns the treatment of seller concentration. Initially, variables for seller concentration turned out to be non-significant. Some recent research has, however, suggested that the effect of foreign competition on profitability is evident only in those industries where seller concentration is high so that the competition among domestic producers is weak. This suggestion is examined in section III...