The effect of relative domain importance as a weighting mechanism in quality of life (QoL) measures has been a topic of debate for decades. Studies investigating the role of domain importance in QoL measures have produced mixed results. The mixed results may very well be the consequences of a limited choice of global satisfaction or QoL measures, measurements of domain satisfaction, measurements of domain importance and weighting approaches applied to date. This study investigated the effect of importance weighting without assigning any arbitrary weighting function of domain importance. A cluster analysis was first used to classify individuals into groups, based on their perceived importance of various life domains, and then the relationship between global life satisfaction measure and the composite of domain satisfaction scores between these groups was compared. Results of this study showed that the relationship between global life satisfaction and composite of satisfaction scores did not remain consistent for respondents with different importance rankings of major life domains, which suggested an important effect of domain importance in QoL measures.