Although self-employment is of interest to many salaried workers who wish to change careers or continue working past the usual retirement age, little is known about the experiences of those who have actually made such a change. Of the 2,326 salaried men who were between the ages of 45 and 59 when interviewed in 1966 as part of the National Longitudinal Survey of Mature Men, 13 percent were found, 12 years later, to have become self-employed at some time before 1978. Becoming self-employed was found to be related to a variety of sociodemographic, work history, and attitudinal variables. The transition rate to self-employment was higher for whites than for blacks, higher for white collar workers than for blue collar workers, and was most common among salespersons, managerial workers, and professionals. Only a minority of those who became self-employed succeeded in their new ventures. About half returned to salaried employment while many others left the labor force entirely. The findings suggest that those considering self-employment should realistically assess the financial resources they can afford to risk, their stamina and physical energy, and their managerial and marketing skills. (Author/NRB)