This paper considers the effects of monopoly third‐degree price discrimination on aggregate consumer surplus. Discrimination is likely to reduce surplus (relative to that obtained with a uniform price), but surplus can rise under reasonable conditions. If the ratio of the pass‐through coefficient to the price elasticity at the uniform price is higher in the market with the higher price elasticity then surplus is larger with discrimination (for a large set of demand functions). The relatively high pass‐through coefficient implies a large price reduction in this market. With logit demand functions surplus is higher with discrimination if pass‐through is above 0.5.