A cytohistological investigation was performed to better understand the structural alterations of cowpea seeds in relation with soaking. Thin sections obtained from seeds soaked at 30¿°C, 60¿°C and 95¿°C were treated to specifically visualize starch, proteins, cellulose and pectin. Micropyle behavior as well as water uptake and dry matter loss were also monitored. A Soaking at 30¿°C induced slight alteration of parenchymatous cells of cotyledons, whereas drastic alterations were observed at 60¿°C and intense alterations at 95¿°C. All these structural modifications of cells could explain losses of nutrients and antinutritional factors at the highest soaking temperature (95¿°C). The size of the apertures in the micropyle sections varied depending on both soaking temperature and time. At 30¿°C and 60¿°C, the micropyle aperture enabled notable water uptake by seeds. At 95¿°C, water was entirely taken up through the testa. These results show that models describing nutrients losses and water uptake should account for these structure changes during soaking of legumes.