Internet service providers (ISPs) are intensively dependent on their customers. Therefore, customer loyalty is crucial for these types of companies. This paper investigates the effects of different variables such as customer satisfaction, service quality, switching cost and corporate image on customer loyalty. Identifying indicators of any variable in this research can help ISPs that their numbers are increasing. Since the internet is becoming pervasive and universal, drawing up effective strategies is beneficial for obtaining loyal customers. The methodology of this research was a descriptive-correlation style. Statistical populations of this research were high-speed internet customers of Saba Net Company in Tehran, Iran. The model of research was evaluated by a sample consists of 384 people and by using a random sampling method. The research instrument was a questionnaire, that its validity was confirmed by the faculty of management of the University of Tehran and specialists and managers of the company in question. The reliability of the questionnaire was assessed by Cronbach’s alpha which value of alpha for all structures was higher than 7.0. The data were evaluated and analyzed by LISREL and SPSS software and the Structural Equation Modeling (SEM) is used as the statistical method. In this research, the effectiveness of several variables such as service quality, customer satisfaction, corporate image and switching costs on customer loyalty were investigated. Among effective factors on customer loyalty, customer satisfaction with an effective coefficient of 0.41 had the most effect. Service quality and switching cost with a reliability level of 95% had a positive and significant effect. Similarly, among two factors of customer satisfaction and service quality, customer satisfaction had more effect on corporate image providing internet services than service quality. Additionally, results showed that corporate image (B = 0.80, T-VALUE =2.80) had a positive and significant effect on customer loyalty. This variable solely indicated 64% of total changes variance of customer loyalty variable.
