In criminology, cohort studies are defined as studies of subjects who are all born within a given period in a given geographic area. Cohort study goals are to explore the criminal activities of a particular cohort in relation to a different cohort, and to characterize the subjects of a particular cohort in their present state and in their development through time. Though similar in method to followup studies and criminal career studies, cohort studies focus on a particular and clearly defined group. In this respect cohort studies resemble generation studies, which focus on a group of persons born during a particular year. However, cohort studies are based on various types of public records while generation studies rely on crime statistics. Among the reasons why criminological cohort studies are still rare is the difficulty of gaining access to and working with voluminous public records and documents in archives and the great costs of such an undertaking. A scientific problem with cohort studies is that the uneven availability and the accuracy of records may distort the results of the study. Nevertheless, cohort studies offer new perspectives in the area of criminology, the criminal, and social reaction by establishing general sociological influences on crime; by furnishing a representative sample population of cohort offenders and a representative control group of nonoffending cohort members; and by showing the influence of social factors like racism or socioeconomic status on the development of crime. The article warns of two dangers inherent in cohort studies: the danger of confusing different levels of criminological interpretation and the danger of confusing epistemological levels of interpretation. Twenty-three bibliographical footnotes are included.