The Caspian Sea region has become a major focus of oil activity since the break up of the Soviet Union. There are four sedimentary basins in the region, each containing substantial proved hydrocarbon reserved. Five independent states (Russia, Kazakhstan, Azerbaijan, Turkmenistan, and Iran) share these reserves. The primary challenges of the are include: high cost of oil and gas transportation; territorial disputes; complicated seismic and geological conditions; and sensitive ecology. Early activity in the region was disappointing; however, several recent oil and gas discoveries, including what may be the largest offshore oil field in the world (Kashagan in the Kazakhstan sector), may renew interest. This paper reviews the major geological features and prospect types, as well as technical and economic developments. Historically, Caspian offshore activity has been mainly restricted to the multinational oil companies. However, recent developments could provide avenues for smaller companies and consortiums to participate. Activity in the area has resulted in new 3D and transition zone seismic data, multi-client seismic surveys and equipment and services on a shared-cost basis. A summary of available reserves and economic cases modelling is provided. Companies that can balance risk and target size, forecast the development strategies, and manage local politics should consider investing in the Caspian Sea region.