This study examines the extent and correlates of moonlighting at various stages in the life course for employed husbands (N = 2,118) in the United States in the mid-1970s. Using data from the Michigan Panel Study of Income Dynamics (1976-1977 waves), the study found that 21% of the husbands held two jobs, a figure substantially higher than official estimates. In estimating the likelihood of moonlighting, using a range of individual, family, and job characteristics, three hypotheses are tested. The first two, drawn from the “life-cycle squeeze” literature, suggest differences in the likelihood of moonlighting at various stages of the life cycle and in conjunction with variations in the wage rate of the primary job. The third hypothesis relates moonlighting to a sporadic work history. Findings reveal that there are indeed variations in the incidence of moonlighting over the life cycle. Moreover, the effects of wage rate and work history interact with life-cycle stage, suggesting that the factors related to moonlighting vary across stages of men's lives.