The husk tomato (<i>Physalis ixocarpa</i> Brot.) is widely cultivated in central Mexico, and may be grown in countries with a temperate climate. The experiment was set up during the dry period of the year (average weekly temperature 17-22°C) in the State of Morelos, Mexico, using the cv. 'Rendidora' in loamy clay soil and furrow irrigation. The roots were investigated by the pinboard method modified by Garcia Blancas and Grajeda Gómez (in print), partly adapted by us for quantitative estimation of root systems. Two plants were investigated every second week. They had a well developed tap root. Most of their lateral roots were found in the superficial soil layer, 0-20 cm. The root dry mass was also concentrated near the central axis of the plant. The majority of root apices were, however, found in the soil cylinders 10-40 em from the central axis. During the senescence of the aerial part (14th week after emergence) the root system lost a large part of its small roots. The modification of the pinboard method, by Garcia Blancas and Grajeda Gómez (in print) permited us investigating the root systems with very simple tools, in situ.