The glycaemic response to eight potato varieties commercially available in Great Britain was compared against a glucose standard in a non-blind, randomised, repeated measure, crossover design trial. Seventeen healthy subjects (three males, fouteen females), mean age 32 (sd 13) years and mean BMI 22·3 (sd 3·6) kg/m2, were recruited to the study. Subjects were served portions of eight potato varieties and a standard food (glucose), on separate occasions, each containing 50 g carbohydrate. Capillary blood glucose was measured from finger-prick samples in fasted subjects (0 min) and at 15, 30, 45, 60, 90 and 120 min after the consumption of each test food. For each potato variety, the glycaemic index (GI) value was calculated geometrically by expressing the incremental area under the blood glucose curve (IAUC) as a percentage of each subject's average IAUC for the standard food. The eight potato varieties exhibited a wide range in GI values from 56 to 94. A trend was seen whereby potatoes with waxy textures produced medium GI values, whilst floury potatoes had high GI values. Considering the widespread consumption of potatoes in Great Britain (933–1086 g per person per week), this information could be used to help lower the overall GI and glycaemic load of the diets of the British population.