The Minnesota Twin Registry is a birth-record-based twin registry. Begun in 1983, it includes data for 4307 surviving intact pairs born in Minnesota between 1936 and 1955. In addition, the Registry includes 901 twin pairs born in Minnesota from 1904 to 1934, as well as 391 male pairs born in Minnesota from 1961 to 1964. The research focus is primarily on human individual differences assessed by self-report. Questionnaires completed by the participants include measures of personality, occupational interests, demographics, and leisure-time activities. We outline major contributions that have resulted from Registry research, as well as current and future research directions.