Ascarisis is the infection caused by Ascaris lumbricoides which can be transmitted through the injection of food, water and vegetables contaminated with the egg of Ascaris. This study was undertaken to evaluate the cidal activity of proteins secreted by Bacillus thuringiensis against Ascaris lumbricoides. A total of fifty soil samples from garden soil were collected and screened for the presence of Bacillus tkuringiensis using pour plate technique. The organisms obtained from mixed culture plates were characterized and identified using their morphological and biochemical characteristics. Cidal activities of the proteins were carried out by exposing 10 of the Ascaris lumbricoides to different concentrations (50.00, 100.00, 150.00, 200.00 and 250.00 ppm) of the secreted proteins. The study revealed the presence of Bacillus thuringiensis isolates; Bt M, Bt N and Bt Y. The maximum spore count was 4.93 logCfu/ml after 96 h. There were pronounced cidal activities of the secreted proteins, mostly from Bt M, and these increased significantly (p< 0.05) as the concentrations of the secreted proteins increased. The LC50 of the study revealed significant (p< 0.05) activities of the secreted proteins against the Ascaris lumbricoides, of which the secreted proteins from Bt M showed the most pronounced activity. Therefore the secreted proteins from the BsD45, BsDSM396, BtDX3 and BtWO15 showed significant larvicidal activities against Ascaris lumbricoides, of which secreted proteins from isolate of Bacillus thuringiensis (Bt) M recorded the most pronounced activity.