Recent studies of European agricultural history have shown that, during the early phases of economic development, agricultural growth can occur in the absence of major institutional changes. This article extends such a conclusion – of agricultural growth without major institutional change – to the case of Portugal during the period from 1850 to 1950. Based on new indices for agricultural output growth and data on the use of inputs, we show in this article that Portuguese agriculture was not stagnant in that century and that output and labour productivity expanded rapidly, in particular in the decades from 1870–1900 and 1930–50. We propose an explanation for the positive performance of the agricultural sector which is related to the changing patterns in the use of land and in the product mix, and to the growth of domestic demand for agricultural produce.