The purpose of this study is to measure customer satisfaction of two mobile operators in Lebanon, Alfa and MTC Touch, from a sample of the telephone customers for these two operators; We draw 500 phone active numbers randomly selected from their system database. After telephone contacts, we were able to record and completed 600 questionnaires referred to the EPSI (European Performance Satisfaction Index) questionnaire made on 23 questions and distributed equally between the two operators; the data collection was carried out between May 2012 and June 2012. The goal is to construct the structural equations modeling and to estimate the measure of customer satisfaction using the ECSI [1] model by PLS approach and build a satisfaction index for each operator. In our work, we discuss the ECSI model (European Customer Satisfaction Index). Indeed, this model solves the main difficulties in measuring customer satisfaction. It provides best reliable results and do better understand and monitor the quality of customer relationship business. The hypothesis are tested and discussed.