Purpose: The purpose of this study was to evaluate the effect of web-based diabetic education on plasma glucose and serum lipids in obese people with diabetes. Method: A random allocation design with control and experimental groups being assessed pre- and post-intervention was used. Eighteen patients were randomly allocated to an intervention group and 16 to a control group. Participants were requested to input their blood glucose levels weekly for 3 months at http://www.biodang.com by cellular phone or wire Internet. The researcher sentoptimal recommendations to each patient weekly for 3 months using a short message service (SMS) of the cellular phone and wire Internet. Results: Patients in the intervention group had a mean decrease of $1.2\%$ in glycosylated haemoglobin ($HbA_{1}c$) levels and those in the control group had no difference in HbA1c levels. There was a significant mean change in 2-hour post prandial blood glucose (2HPPG) for the intervention group, with a mean change of -120.1 mg/dl. The mean change in the control group, however, was not significant. Conclusion: These findings indicate that this web-based intervention using SMS of the cellular phone for 3 months improved $HbA_{1}c$ and 2HPPG, but did not affect total cholesterol, triglyceride, and high density lipoprotein cholesterol in obese type 2 diabetic patient.