This paper presents an integrated study of price-cost margins and scale economies. The model is estimated on the basis of a comprehensive data set for individual establishments covering almost the whole Norwegian manufacturing sector over the period 1975-90. For most manufacturing industries prices significantly exceed marginal costs. However, the price cost margins are fairly small (1.06-1.16) compared to other findings by Hall (1988) and others. There is a tendency for larger finns to obtain a higher markup. None of the samples reveals significant scale economies, while 7 out of 20 samples exhibit moderate decreasing returns.Financial support from NORAS/LOS is gratefully acknowledged
