The increased skin cancer incidences are important public health problems. In spite of the strong promotion of the UV-index as essential UV risk education tool, only few studies have investigated peoples understanding of the UV-index. This paper is the first to present representative data on UV-index understanding in Germany. In 2007, a representative telephone survey was carried out among 1,501 German residents aged 14 years and older. Only 27% of the respondents had heard of the UV-index before and 17% of the German respondents claimed to consider the index for their sun habits. Less than 10% of the German population was able to attribute the correct meaning to the UV-index as well as know their own skin type. The results of the present study suggest that informing the public about the UV-index has very limited impact on the public's understanding of the UV-index as well as on their attitude toward sun exposure. The results warrant the question whether the UV-index in the present form is a useful education tool in UV risk communication.