Billing system is a massive investment for telecommunication operators. Currently, there are various billing system providers on the market that offer many features and convenience of usage, such as Amdocs, Convergys, Oracle, Nokia Siemens, Huawei etc. Telecommunication operators then must be able to choose a billing system that suits their needs and provides return on investment for the company. This study identifies the features of the eTOM framework, particularly the area of the Billing & Revenue Management, along with features from Amdocs, Convergys and Oracle, then categorizes, and organizes a group of common features of the billing system. After that the general features are analyzed by using the Ranti's Generic IS/IT Business Values table for identifying the potential benefits of billing system investment. Based on the analysis from the Ranti's Generic IS/IT Business Values table, 8 (eight) groups of IT investment benefits are produced, which are increasing revenue caused by reducing cost of delivery, office supplies and printing; accelerating process of transaction and report making, reducing risk of unrecoverable claim and penalty; accelerating process of production; increasing accuracy of data, billing, and increasing service quality; increasing other incomes; increasing productivity caused by restructuring job function; offering substantial discounts; and avoiding cost of maintenance. These eight groups of the IT investment benefits then can be used as reference by telecommunication companies to measure the IT investment benefits of billing system.