Indonesia's telecom industry is experiencing intense competition with a price reduction strategy that has resulted in a price war. Although price war has received a lot of pressure from the business side and has attracted the attention of some researchers, it still does not explain how they affect customer behavior. Therefore, this study aims to specifically investigate customer's behavior in choosing cellular operators due to the price war strategy that occurs among cellular operators in Indonesia, especially DKI Jakarta. This research used quantitative research methods by collecting data through distributing questionnaires to several respondents. Descriptive statistics analysis was being used to describe the results of customer data collection. The results showed that customers from various amounts of income chose quality of service as the main factor that helped them chose a cellular operator, followed by low package prices as the second factor. The results also showed that the impact of the application of promo tariffs by operators to increase the number of sales and customer, caused customers to choose cellular operators that offered low prices with large quotas. Customers from various income levels would also switch to other cellular operators if the service quality provided by operators was bad.