Background:
Vietnamese government is targeting at achieving tobacco control goal with 10% reduction by year 2020. In the last two decades, cigarette price in Vietnam have not been increased. According to article 6 of FCTC, raising the cigarette price is known as one of the most effective strategies to combat cigarette smoking. The aim of the study was to estimate the required price that would make smokers attempt to quit and identify the predictors of required price to quit.

Methods:
A cross-sectional survey was conducted with a total of 820 current smokers who live in third largest city of Vietnam. A structured questionnaire was adopted from International Tobacco Control (ITC) project surve. Bayesian quantile regression and Bayes factor were applied to predict factors associate with cigarette required price.

Results:
Out of 56% (461 people) of smokers were suggested price to quit with age range from 18 to 65 years. The median required prices to quit per pack, US $ 2.7 IQR (~2 to 4.4), increased 2.8 times (2.04 to 4.54) higher than usual price (~ US $ 1). If the required price reaches to at median price (higher 2.8 times), 56% of smokers suggested price tend to be quitting seriously. predictors of cigarette price were significantly associated with the lower required price including perceived awareness of warning label, smoke-free workplace and receiving advices from physicians. In contrast, high educations, having good health, heavy smoker and failure of quitting were significantly associated with the higher price across all quantiles.

Conclusions:
These results suggest the potentially useful approach to setting price increase in Vietnam. Require prices have been considered various factors regarding non-tax policy and quit intention, and appropriate approach to those group with failure quitting history, high education, heavy smoker