Changes in the rapid visco-analysis (RVA) viscosity of potato and waxy maize starches during digestion were studied using amyloglucosidase and α-amylase (60–1700 U/mL), and three solids contents (3–20%) of the starch dispersions in a replicated randomised experiment. The starches were gelatinised in the RVA before digestion at 50°C at a shear rate of 17 s−1 for 5 min. Control dispersions effectively did not change (<10%) in viscosity with time. With the enzyme-treated gels, irrespective of the starch, enzyme or concentration, the RVA viscosity reduced with time as low molecular weight (MW) products were produced. A modified first-order kinetic model suitably described (r2>0.9) the starch viscosity-digestograms. The rate of change in starch viscosity, KVIS (an index of the rate of starch digestion), was significantly (p<0.05) inversely related to the solids content, and directly related to the enzyme concentration. KVIS of the waxy maize starch was higher than that of the potato starch, and a higher KVIS was measured with the α-amylase than with the amyloglucosidase. Differences in potato and waxy maize starch structures, specificity of enzymes and enzyme:substrate ratios can explain the results, and rheology is proposed as valuable in starch digestion.