Abstract To survive in the challenging environment of a global market, organizations must recognize and analyze customer attitudes. To be competitive, organizations must recognize and forecast customer preferences and behaviors to maximize customer retention before their rivals do so. This research identifies factors that affect customer churn, the single most valuable of an organization's assets. One year's data from call log files relating to 3150 customers were selected randomly from an Iranian mobile operator call-center database. Binomial Logistic Regression was the method of analysis used in this research. The results of this research indicate that a customer's dissatisfaction, their amount of service usage and certain demographic characteristics have the most influence on their decision to remain or churn. The results also imply that customer status (active or inactive status) mediates the relationship between churn and the cause of churn. The Iranian government's current plan to privatize the telecommunications industry without deregulation leads to a non-square competition environment. Deregulation in favor of delegating more authorities of customer care is necessary in order to develop a square private competition environment in the Iranian mobile telecommunications industry.