Facing the new market challenges, service providers are looking for solutions to improve three major business areas namely the Customer Experience, The Operational Efficiency and Revenue and Margin. To meet the business requiements related to these areas, service providers are going through three major transformation programs namely the Business Support Systems transformation program for Customer related aspects, the Operations Support System transformation program for mainly service Fulfillment and Assurance and Resource, Fulfillment and Assurance, and Time To Market Transformation program for Products ans Services development and management. These transformations are about making a transition from a current situation with all its views to a desired one. The information view transformation is about reorganizing and reengineering the existing information to be used for the day to day activities and reporting to support decision making. For reporting purpose, service providers have to invest in Business Intelligence solutions. For which the main purpose is to provide the right information in a timely manner to efficiently support the decision making. One of the key BI challenges is to model an information structure where to host all the information coming from multiple sources. The purpose of this paper is to suggest a step by step methodology to design a Telco Data Mart, one of the fundamental BI components. Order-To-Payment, an end to end customer process, will be used as an application for this methodology. Our methodology consists on bringing together the concepts of business intelligence and the telecom business frameworks developed by the TM Forum: the Business Process Framework, the Information Framework, and the Business Metrics. The advantage of this solution is its ability to adapt to any telecom enterprise architecture since it's built around the business standards.