The effect of cassava brown streak disease on cassava root storage components was studied for four Ugandan varieties with varying levels of tolerance. Significant differences (p<0.05) were observed with reductions of 30% in amylose content and 50% in amylopectin content of diseased compared to healthy plots. Average dry matter content of diseased plots was 25% higher than starch yield, and starch content reduced by 40% and 15% respectively in diseased plots compared to healthy plots. Susceptible varieties had lower protein and higher cyanide contents in a diseased state compared to tolerant varieties. On pasting, mixed reactions were observed, but importantly there were significant differences (p<0.05) in the starch-pasting properties of starch from diseased plots compared to that of healthy plots. Plants with similar reactions to viral attack at the phenotype level had different reactions when the levels of results pointed to hijacking of plant carbohydrate.