In most developed countries we observe an increasing share of part-time farming at the expense of full-time farmers. In the present paper, we develop a theoretical labour supply model which accounts for the specific decision problem of a farmer. The empirical analysis uses the ordered probit and a Tobit model to explain labour supply behaviour for a sample of farm households in Upper Austria. Farm size, household characteristics, as well as education significantly influences off-farm labour supply behaviour. The obtained wage elasticities for male farmers are comparable in magnitude to those obtained in labour supply studies for adult females or elderly people.