Cassava (Manihot esculenta Crantz), due to its starchy roots is a potential raw material for the biofuel market. To modify the starch quality/quantity in cassava, we used RNA interference (RNAi) to silence selected genes of the starch biosynthesis pathway in the roots. Genes coding for GBSS, SBE & AGPasa were PCR-amplified and cloned into the silencing vector pHELLSGATE. The constructs were introduced in cassava cultivar 60444 by cocultivating Friable Embryogenic Callus (FEC) with Agrobacterium. After several transformation attempts, only two lines of plants were confirmed by Southern blot as transgenics for construct pHELLSGATE::SBE. These lines showed abnormal growth and deformed leaves. These findings suggested that silencing genes of the biosynthesis pathway in cassava may compromise the viability of plants.