The purpose of this paper is to contribute some new measurements to t112 discussion of trends in the terms of trade between manufactured goods exports of developed countries and primary product exports of developing countries. The new measures are manufactured goods price indexes that are derived from price data rather than from unit value data and include some corrections for quality change. Our calculations indicate that the prices of manufactured goods exported by developed countries to developing countries have risen over twenty years or so by 75 per cent, as compared to the 140 per cent shown by the generally used UN unit value indexes. The decline in terms of trade for these goods relative to primary products has been almost 50 per cent over this period. Over tile last hundred years, fluctuations in the terms of trade of manufactured goods relative to primary products !lave been very wide, as far as we can tell from the inadequate measures we have. Impressions about trends have been highly dependent on choices of beginning and end years. There is very little evidence for a long-run trend in either direction.