To investigate the change in GMP 140 and its significance in patients with diabetes accompanied with cerebral infarction. Plasma GMP 140 levels were assayed by radilimmunoassay in diabetes accompanied with cerebral infarction, controlled diabetes, cerebral infarction patients and normal controls, respectively. The results showed the GMP 140 levels were significantly higher in patients with diabetes accompanied with cerebral infarction than in patients with diabetes and normal control ( P 0 05). The results suggested that the level of GMP 140 in plasma might be used as a sensitive and reliable indicator reflecting the degree of platelet activation.