We studied the acute effects of cigarette smoking on glucose tolerance, heart rate and blood pressure in smoker and non-smoker group. Two 75-gram oral glucose tolerance tests (OGTT) were performed in 6 healthy smokers and 6 non-smokers at an interval of one week. The subjects smoked one cigarette at each time period of 0, 15, 30 min during the second OGTT. Serum glucose, insulin, and C-peptide levels measured every 30 min and blood pressure with heart rate every 10 min for 120 min during 75 g OGTT. The results are follows 1) In non-smokers, serum glucose and insulin levels showed an increased tendency at 30 min during smoking OGTT comparison to control OGTT. C-peptide level at 30 min during smoking OGTT was 12.1+/-6.2 microIU/microliter, which was significantly higher than that during control OGTT (7.5+/-2.9 microIU/microliter) in non-smokers (p<0.05). 2) In non-smokers, systolic blood pressure during smoking OGTT was 123+/-8.0, 130+/-7.8, 127+/-7.5, 130+/-7.6 mmHg respectively at 10, 20, 30, 40min, while systolic BP during control OGTT was 114+/-3.4, 114+/-7.9, 115+/-8.2, 115+/-6.4 mmHg (p<0.05). 3) In smokers, there were no significant difference in blood sugar, insulin, and C-peptide levels between control and smoking OGTT. But heart rate from 10 to 60min and systolic pressure from 20 to 40 min during smoking OGTT were significantly increased (p<0.05). 4.6, 110+/-6.2 mmHg during control OGTT respectively (p<0.05). Above results suggest that smoking acutely induces a transient hyperinsulinemia with glucose intolerance, and is related to insulin resistance.