Using data from four large, national probability samples followed longitudinally, this study investigated changes in locus of control orientation from the late 1960s through the late 1970s. The sample consisted of four cohorts who participated in the National Longitudinal Surveys of Labor Market Experience (NLS): mature men (ages 45-59), mature women (ages 30-44), young men (ages 14-24), and young women (ages 14-24). Each subject was administered a locus of control scale three times over a 7-8 year period. The scale was an 11-item abbreviated version of Rotter's Internal-External Locus of Control Scale (I-E; Rotter, 1966). The findings showed close similarity in locus of control scores among the four groups in the late 1960s and the early 1970s. However, by 1976-78 both groups of women had moved substantially toward the external end of the scale, whereas both groups of men remained basically unchanged. Changes in scores for women could not be accounted for by demographic factors entered into multiple regression analyses. The authors suggest a "cultural-shift" interpretation of the sex differences found in this study: Women in the mid-1970s became more aware of the external constraints on their ability to meet their goals in the labor force and other settings; men as a group presumably did not experience similar changes in their perceptions. Overall, the findings presented here document a major divergence between the sexes on perceived control during a decade when sex role issues reached national prominence.