Introduction : Unplanned Teenage pregnancy is becoming a serious problem in many countries, including Thailand. It creates many related impacts such as health, economic, social and cultural problems. It is surprising that the rate of teenage pregnancy increases each year. According to the records of the Health Department, it shows that the rate of teenage pregnancy in Thailand in April, 2008 had increased to 14.7%, while the World Health Organization recommended that it should be no greater than 7%. The actual rate of teenage pregnancy is still in doubt and difficult to be evaluated as the records of the Health Department consist of only teenage mothers who wish to continue their pregnancy, it does not include the rate of criminal abortion. So the actual rate of teenage pregnancy ought to be greater than the rate in the official report. So it can be stated that unplanned teenage pregnancy is a major problem in Thailand and it needs to be solved. However, unplanned teenage pregnancy CAN BE PREVENTED. The prevention of this situation should be managed urgently.