OBJECTIVES:  A valid cost-effectiveness threshold was required for every country to conduct cost-effectiveness analysis. Among several measurements for cost-effectiveness threshold, willingness to pay (WTP) per a quality-adjusted life year (QALY) has been used widely. This study aim to determine the value of WTP per QALY as well as possible influencing factors. METHODS:  Cross-sectional study using face-to-face interview technique. The EuroQuality of life – 5 Dimensions – 5 Level (EQ-5D-5L) has been used to estimate the patients’ QoL. The value of WTP per QALY was gained through bidding game technique in one scenario of improving patient’s current state to perfect health by hypothetical treatment. The randomized sample based on inclusion and exclusion criteria has been chosen from January to March 2016. RESULTS:  Study sample included 252 outpatients at Heart Institute in Ho Chi Minh City with average age at 52.46 ± 0.65, the gender ratio between male and female at 1:1.02, most patients from urban area (54.8%), average monthly household income at 15.8 ± 0.99 million VND. Three out of fourth patients visited Heart Institute for the first time, most of them (93.7%) had not had medical intervention in the past and health utility of patients derived from EQ-5D-5L questionnaire with index-based Thailand value set at 0.7474 ± 0.0097. The value of WTP per QALY was 50.1255 ± 3.3585 million VND/QALY and ranged from 0.33 to 144.4 million VND/QALY. The influencing factors included gender, living area, household income and health utility. CONCLUSIONS:  The value of WTP/QALY explicated from this study is approximate with GDP per capital in Vietnam as recommended by WHO-CHOICE for Southeast Asian countries. This result can be used as an indicator of financial ability in patients with cardiovascular diseases, a threshold in cost-effectiveness analysis and as preference data for health care service planning.