To see whether food form, the degree of cooking, or protein enrichment affected the glycemic response to pasta, we gave test-meal breakfasts to 13 diabetic patients. Macaroni had a significantly greater glycemic index (GI) (68 ± 8) than spaghetti (45 ± 6, P < .01); the GI of star pastina was intermediate (54 ± 6). The GI of spaghetti was not significantly affected by cooking for 5 or 15 min (45 ± 6 and 46 ± 5, respectively), or by protein enrichment (38 ± 4). The GI of spaghetti was similar in 11 noninsulin-dependent and 6 insulin-dependent diabetic patients (49 ± 7 compared with 57 ± 8). We conclude that different types of pasta may produce different glycemic responses but that these are not necessarily related to differences in cooking or surface area.