Perceptions of personal control were studied in 1267 individuals who represented four generations of families participating in a large longitudinal study spanning 1971 to 1991. Cross-sectional, longitudinal, and sequential analytic strategies were employed. Over 20 years, mean levels of personal control became more internal in the 560 respondents who participated at all four times of measurement, probably as a reflection of contextual factors in the culture. Developmental changes toward greater internality were indicated for young adults as they progressed into middle age. Cross-sectional differences in middle-aged and older adults did not appear to represent developmental differences. The oldest generation of women was consistently the most external subgroup, suggesting a cohort effect reflective of their socio-historical reality.