Based on a conceptual framework, we develop the hypothesis that part-time farmers invest in less profitable products than full-time farms, due to the necessary minimum labour requirements which entering and running profitable production processes require. Descriptive statistics for Swiss farms show some indications for this hypothesis, like a much lower total revenue and lower agricultural income of part-time farms, despite a comparable value of the farm’s assets. A regression analysis for the period 1996-2005 confirms that Swiss part-time farms tend to focus on products with low labour profitability. This may explain why part-time farming in Switzerland is less developed than in most other European countries, and raises the question whether part-time farming offers a solution for structural change process in small-structured agricultural systems affected by imperfections on factor markets.