As a basic standard of life, internet connects millions of computers in a global network. People use, participate, or access the internet with the help of internet service providers (ISPs). To have better quality of connection, customers are prone to change their ISPs. In the competitive environment, ISPs endeavor to prevent losing their customers which are referred as churn. Thus, churn management takes an important place for ISPs. To investigate customer loyalty status, behavior, and information of the churn possibility in Turkey, a questionnaire is implemented. By using a real data obtained from a survey, promising and applicable results are obtained to predict the churn behavior of ISP customers in Turkey. As an extension of the study, the questionnaire will be applied for a larger population to find accurate results about churn situations. This study will help ISP companies to determine the required advertising campaigns for the customers.