Abstract: The Fukushima Daiichi nuclear accident on 11 March 2011 was a consequence of the 9.0 magnitude Tōhoku earthquake and the following tsunami. A series of ongoing equipment failures in several units of the power plant led to releases of radioactive material into the atmosphere and the seawater. Based on these emissions, the accident was regarded as a level 7 (major accident) on the International Nuclear and Radiological Event Scale (INES). The emissions caused significant radiation and isotope concentrations measured in the environment by involved institutions. Measurements were performed on different media like soil, water, and foodstuffs. Based on these monitoring data, the authorities in Japan implemented emergency measures to protect the population of the region. These measures were, for example, evacuating the people from the zone where high gamma dose rates were detected or banning contaminated foodstuffs with respect to existing limit values. Direct and indirect effects of the releases in Japan could also be observed in Europe. However, it should be noted that the measured values were far below those values that could affect human health.