The lack of appropriate production data has hitherto hampered any attempt in estimating changes in labour productivity in pre-industrial economies. The method applied here estimates labour productivity by making inferences from available information on changes in the occupational structure, relative wages, and foreign trade. The accounting procedure is based on the assumption that the consumption function is stable over time and applied to two advanced regions of medieval Europe. Changes in the proportion of non-food procedures may imply a change in agrarian labour productivity provided changes in trade in food and relative wages are controlled for. The regions investigated exhibit growth rates around 0.1 - 0.25% per year in the pre-plague period.