Norwegians have a long tradition in underground work which is clearly exhibited in Oslo. Although a small (500,000 inhabitants) and fairly spacious city, with variable rock quality, the underground is utilised to a large extent. The ever increasing focus on environmental aspects, and the soaring cost of land, have made underground solutions increasingly favorable for all kind of utilization. Traffic systems for road, metro and railways; collection and conveyance systems together wíth treatment plants for water supply and sewerage; sport arenas and car parkíng,- energy generatíon; control systems; oil and food storage. Roughty 180 km of tunnels and additionally 1,500,000 m3 of caverns are located in the Oslo area. The paper, describes the ground condition and rock work methods in general and some of these ínteresting projects in particular.