Customer satisfaction is commonly acknowledged as one of the useful proxy measures of ecommerce system effectiveness, which in turn leads to business success. This study proposes an effective ecommerce system development by means of the conceptualization and measurement of an e-commerce user satisfaction index. The proposed construct is defined and empirical validation of the index and its dimensionality is provided. This proposed instrument will be useful to researchers in developing and testing ecommerce systems theories, as well as to organizations in designing better-accepted e-commerce systems.