Tuta absoluta, Bemisia tabaci and Macrosiphum eurphorbiae are important pests of tomato in Cameroon. The effect of EM a biopesticide containing Bacillus thuringiensis as active ingredient was evaluated on the suppression of these pests. A completely randomized design with 4 treatments [control (T0); EM 10 ml/l (T1); EM 20 ml/l (T2); EM 30 ml/l (T3)] and 3 replications were used. The biopesticide was sprayed weekly for seven weeks. The variation of insects' populations, T. absoluta impact and plants growth in different plots were compare using ANOVA test. Different concentrations of B. thuringiensis were effective in reducing pests populations and significant difference observed within treatments (DF =3, F=258.69, P=0.0000; DF=3, F=368.50, P=0.0000 and DF=3, F=44.21, P=0.0000) respectively. On the untreated control plots T0, the populations of the three pests showed an exponential expansion within 7 weeks. No significant effect of B. thuringiensis was observed on the plant growth. This biological pesticide can save as alternative pests control for sustainable tomato production.