The objectives of study were to study towards cigarette smoking behavior of youth from the cigarette tax increases in 2017 and to study the factors affecting the decline of youth smoking from the cigarette tax increases. The sample group used in the study was undergraduate students of Kasetsart University, Bangkhen Campus, and collected data by using 400 sets of questionnaires. Data were analyzed by using descriptive statistics such as frequency, percentage, and Binary Logistics Regression. The results revealed that the factors affecting the decline of youths smoking from the cigarette tax increases were statistically significant which consisted of the characteristics of accommodation, cigarette brands, smoking frequency, changes in cigarette brands, or types after cigarette tax increases. There was a positive correlation between the attitude towards the increases in cigarette prices and the reduction of smoking expenses. In other words, students who do not live with their parents will be smoking imported brands occasionally. If students change the cigarette type or brand after the cigarette tax increase and have an attitude towards the increase in cigarette prices in terms of reducing smoking costs, there will be the opportunity to decline smoking after the cigarette tax increases. In terms of education level, the status of parents has a negative correlation. In other words, students with higher education level and the status of their parents are divorced or separated, students will have the opportunity to reduce smoking after the cigarette tax increases have been declined.