Differences between part-time farmers and full-time farmers are examined both theoretically and empirically. We develop the hypotheses that capital to labour ratio, labour productivity in the provision of both private and public goods, and agri-environmental payments received are higher for part-time farmers. FADN data for Swiss dairy farms in 2004 confirm the higher capital to labour ratio as well as higher agri-environmental payments for part-time farms, albeit no differences for the labour productivity of milk production.