This article discusses the difficulties in using nineteenth-century census data relating to occupations for the analysis of sectoral labour inputs. The under-recording of seasonal and women's work in the census shifts in occupational classifications, and the systematic removal from the occupied population of women workers is revealed. Reworking of the census figures suggests the possible need to increase the size ofthe agricultural workforce by between 30 and 40 per cent in the mid-Victorian period. A programme of work is suggested to establish a standardized occupational classification system for census data and to estimate labour inputs from farms.