Network operators and service providers are faced with technology and marketplace changes. Enhanced decision-supporting capabilities are needed to respond quickly to these changes. In this paper we present a system which applies a data warehouse approach for collecting and analysing data from an Intelligent Network to support business decision support systems. The system continuously gathers data from disparate systems in different formats, transforms the data into a consistent format and loads it into a database. Sophisticated and flexible analysis report facilities are provided, which are important for network planning, system operation and marketing.