This article studies the impact of the labour force composition of farms – the share of family labour, permanent hired labour, and seasonal hired labour – on farm productivity. A simple transformation of a Cobb-Douglas function allows us to estimate the relative efficiency of each labour force. Our estimation is based on specialised fruit and vegetable farms over the period 1995-2006 drawn from the French sample of the Farm Accountancy Data Network (FADN). We show that the labour force composition affects the farm’s productivity and that family workers are less productive than hired workers even if the specialisation of some hired worker in seasonal high productivity tasks is taking into account. The results suggest that this difference is linked with productivity gains inherent to task specialisation. We also find that seasonal workers are not less productive than permanent ones altought seasonal work in agriculture is synonymous with low earnings, job insecurity and absence of career development.