The past 15 years have witnessed a growing interest in studies of bullying in the area of work and organizational psychology, but the results of research on this topic seem to indicate very wide variations in the prevalence of bullying. The range of differences may be primarily due to the utilization of different categories and operationalizations of the concept. The aim of this study is to discuss definitions and delimitations of the phenomenon known as bullying, and to demonstrate empirically how the prevalence of bullying can be determined by the way in which it is defined and delimited. On the background of a discussion of some current definitions of bullying and a survey of some central research results on its rate of occurrence, this study presents the results of a study of 3,024 public-sector employees. The results showed that 1.0% of the sample reported that they had been bullied weekly during the previous six months, while 4.7% reported themselves as having been exposed to acts of bullying with the same frequency and for the same period of time. If we change the criteria from "weekly" to "2-3 times a month" the prevalences rise to 3.7% and 26.9%. Based on observations of bullying the prevalence is 3.3%. The results are discussed with reference to other studies that are comparable in terms of delimitations and rates of occurrence and it is concluded that the prevalence is at the same level as these.