The interaction between the seed-dressing fungicides Monceren, Vitavax 200, Rizolex T, and Beret MLX. and the insecticides Nuvacrone, Azodrin, and Kalthane S was evaluated under field conditions in Assiut and Mallawy, in 1998. As a general rule in Assiut, and in most cases in Mallawy, the tested fungicides were effective in increasing stand and yield when they were used in the absence of insecticides; however, they showed a decline, or even complete loss of efficiency when they were used followed by the application of insecticides. The present study demonstrates the potential detrimental effect of using certain insecticides on the efficiency of seed-dressing fungicides commonly used for controlling cotton seedling damping-off, and suggests the importance of studying the interactive effects among pesticides before they are recommended for commercial use.