This study has three objectives: 1) To explore components, indicators and methods for the composite index of objective well-being; 2) To explore differences of the composite index of objective well-being according to sex, age and occupation group and; 3) To conduct a quantitative study exploring the relationship between subjective and objective well-being. The researcher employed secondary data from the “Well-being Indicators: The Study in Western Thailand” Project conducted in Chainat by the Institute for Population and Social Research, Mahidol University, and selected 1,838 people aged 20 years and over as samples The composite index was composed of 6 components and 16 indicators. The researcher applied three methods to measure the index: Self-assessment of subjective wellbeing with the score ranged from 0 to 10; Assessment of the composite index of objective well-being with equal weighted components and; Assessment of the composite index of objective well-being with different weighted components. The study revealed that there was a significant unidirectional relationship between subjective and objective well-being. In other words, objective assessment can be replaced with subjective assessment. In addition, men were found to have a higher level of subjective and objective wellbeing than women. People of older ages had a decreasing level of both well-beings. Agricultural workers had a greater level of objective well-being than non-agricultural workers. After setting the composite index with differently weighted components reflecting reasons for happiness given by the samples, the levels of ther composite index produced were higher than those indices set for equal weighting and subjective assessment. Therefore, policymakers should rely more on people’s opinions about well-being to better lay down policies for people’s genuine well-being in the future.