The interest around the emerging Grid paradigm has grown very much in the last years not only within the research community but also in business and enterprises. Grids allow people and organizations to share their resources over the Internet making possible the exchange of intensive computational power as well as data and instruments as they were super virtual computers. In this paper we introduce SAGE (Storage Accounting for Grid Environments). SAGE is a system to meter the usage of storage resources in a gLite based grid infrastructure whose main task is to collect information from physical devices and make this data available to DGAS (the accounting system of gLite) to account the storage at higher levels. Furthermore, SAGE will provide a storage level usage monitoring system that can be easily accessed through the web or command line tools.