Systematic monitoring of radioactivity in the environment and food has been going on in Switzerland since the mid 1950s. This report contains a summary of the values measured in 1994, along with the interpretation of the data and the resultant radiation doses for the population. The monitoring programme deals with radioactivity in the atmosphere, precipitation, aquatic systems, grass, foodstuffs and the human body, but also includes natural radiation, doses due to radon inside dwellings, emissions from nuclear power stations and other installations using radionuclides and also miscellaneous radiation sources. With only one exception, the nuclear power plants and other facilities licensed to handle radioactive substances remained within their annual emission limits in 1994, and measurements carried out in the environment revealed no inadmissible immission or dose values. The population`s mean annual radiation dose totals 4 mSv. Some 40% of this is due to radon in the home, with extreme values as high as 100 mSr; 30% may be ascribed to natural radiation, roughly 25% to medical applications of ionising radiation, leaving less than 5% ascribable to man-made sources. (author) figs., tabs., refs.