Teenage pregnancy is an important issue. Many countries are paying attention to it. The policies in Thailand and the measures being taken to combat teenage pregnancy indicate that administrators and the public are taking the issue very seriously. Solving the problem of unwanted teenage pregnancy in Thailand was the first subject on the agenda of the National Health Assembly of 2010. The research topic of “the decrease of teenage pregnancy” was proposed for the prioritization of research topics in the Thailand health system in 2010. As a result, the HITAP has taken the researches in the development of surveillance system to monitor, evaluate, and forecast the situation and impact of pregnancy on Thai teenagers.