The paper presents an autonomous robot for removing the leaves from cucumber plants grown in a high-wire cultivation system. Leaves at the lower end of the plants are removed because of their reduced vitality, their negligible contribution to canopy photosynthesis and their increased sensitivity for fungal diseases. Consuming 19% of the total labour input, leaf removal is considered by the growers and their staff as a tedious, repetitive and costly task. Automation alleviates their job and results in a significant cost reduction. Additionally, removal of the leaves results in an open structure of the canopy in which the fruit is clearly visible and accessible which is an advantage for automatic cucumber harvesting. The paper describes a functional model and results of a field test of the de-leafing robot. The field test confirmed the feasibility of the concept of the de-leafing robot.