According to recent research, the knowledge of species, interest in nature, and nature experiences are the factors that best promote interest in and understanding of environmental issues and sustainable life style. However, during the past 20 years the knowledge of species has decreased alarmingly among pupils, but also among their teachers. The aim of this study is to make a survey of student teachers' level of knowledge of species and of factors that have influenced their interest in and capacity for identifying species. Totally 335 student teachers were tested through a species identification test, a questionnaire, and completing interviews. Pupils in grades 7 and 9 and adults were used as reference groups. Student teachers had very varying levels of knowledge of species. Most of them, however, considered it useful to know the most common species of plants and animals in their local environment. The student teachers who had nature-related hobbies as well as practical nature studies in their education, had a considerably better level of knowledge than the others. More than 25 % of the student teachers, however, had a lower level of knowledge (of species) than the average pupils in grades 7 and 9.