The glycemic response following ingestion of carbohydrate in various forms is different. The factors involved are not fully elucidated. In this study the glycemic and insulin responses to 50 g of carbohydrate in the form of white bread (WB), semolina bread (SB), white spaghetti (WS) and wholemeal spaghetti (BS) were compared in ten noninsulin-dependent diabetics. The responses were assessed by calculating the area under the curve. WB and SB had significantly higher glycemic responses compared with WS and BS (P less than 0.01). There was no difference in glycemic response between either form of bread, or either type of spaghetti. Similarly WB and SB had greater insulin responses than WS and BS (P less than 0.05). There was no difference in insulin response between WB and SB but BS had a greater response than WS (P less than 0.01) attributed to the higher protein content of BS. Thus, in this study the physical form of the food was a major factor influencing the glycemic response, and other factors such as particle size and fibre content had negligible effects.