The effects of sucrose on the physical properties of cassava starch aqueous systems were investigated at varied concentrations of cassava starch (5-15% w/w) and sucrose (0-40% w/w). The peak viscosity and the final viscosity during a gelatinization-retrogradation cycle were determined based on a Rapid Visco Analyzer (RVA) test. Sucrose generally increased the viscosity values, while such increments were more pronounced at higher starch concentrations. The water activity and the fraction of freezable water of gelatinized systems decreased with increasing sucrose concentration. These results suggest that the major role of added sucrose is the reduction of water available for starch, thereby increasing effective concentration of starch during gelatinization and enhancing successive retrogradation.