Insect pests are a major constraint to cotton production. In order to find an alternative to chemical control of Aphis gossypii, the insecticidal effect of Thevetia oil and Top bio (based on neem seeds), was evaluated in the field on cotton aphids and their predators in Benin. Thevetia oil at 0.1 and 0.2 liters per hectare and Top bio at 2 and 3 liters per hectare were tested in comparison with the agri-bio-pesticide used by organic cotton farmers at the rate of one liter per hectare and an absolute control (untreated) in a Fisher block design. The agri-bio-pesticide was derived from neem seeds, indigenous «koto» soap and pili-pili pepper. Observations and measurements focused on the population level of A. gossypii and its predators and then on yield. The results obtained revealed that thevetia oil and Top bio significantly (p<0.05) reduced aphid damage on cotton at their low dose. Cotton plots treated with 1% Thevetia oil had more ladybugs (0.09±0.016) than those treated with Top bio at 2 l/ha (0.02±0.016). Agri-bio-pesticide and Top bio at 2 l/ha reduced the number of ladybirds compared to the «Untreated», while Thevetia oil did not. Thevetia oil and Top bio did not reduce the number of spiders compared to Agri-bio-pesticide and «Untreated». Biopesticides did not reduce the number of ladybugs and ants compared to the «Untreated». These predators can be used effectively as biological control agents in an integrated pest management strategy for cotton using these biopesticides.