The influence of soil mechanical constraint on root exudation by maize cv. Dea was investigated. Plants were grown under axenic and hydroponic conditions for 18 days. Mechanical constraint was simulated with glass beads of 1 mm diameter. This treatment was compared to a control without beads. Results showed that plant growth was affected by enhanced mechanical constraint. Observed as reductions in root and shoot biomass, mechanical constraint also stimulated exudation of water soluble organic compounds. Stressed plants lost more nitrogenous compounds than control plants, and therefore, the percentage of released carbon decreased. However, the production of root mucilage was only slightly different.