Underground gas storage is a common activity in countries with major transport and distribution gas pipeline infrastructures, which allows to efficiently resolve demand seasonality problems. So far, Argentina, with major winter demand peaks and its fields located thousands of kilometers away from consumption centers, has not developed UGS facilities, despite the maturity the industry has reached in the country, which has one of the highest rates of natural gas participation in the power matrix worldwide (47%). The first ever underground gas storage project in Argentina is being carried out in the Diadema field, located near the city of Comodoro Rivadavia – Province of Chubut, with injection and withdrawal operations starting as of 2001. (Fig. 1) The goal of this project is to contribute to modulate oil and gas production in the fields of the region, transporting and storing part of the overproduced gas in the Austral and San Jorge Basins during summertime, to have the necessary gas available during the winter peak season, allowing producers to comply with their contract obligations. With this goal in mind, several studies have been carried out, including reservoir modeling and simulation studies, gas injection and interference tests, the workover of gas input wells and monitoring wells, as well as the construction and revamping of the necessary surface facilities for storage operations. Considering the size and geographic location, the Diadema project will be a pilot operation in the region, which will serve as a model for future undertakings.