In many developed countries, the share of permanent hired labour in the total agricultural labour force has been increasing in recent years. Using data from the 1988 and 2000 agricultural censuses in France, we analyse the factors that influence households' decisions regarding the use of hired labour. We show that the increase in permanent wage employment observed over that period results from two opposite trends: an important increase in the proportion of family farms using permanent wage labour and a slight decrease in the average volume of permanent hired labour per employer. The first trend was mainly due to an improvement in family labour productivity and to a sharp rise in farm size, whereas the second results from a rise in agricultural wages, and possibly also from an increase in the productivity of hired labour.