The transitions of women into and out of part-time work were studied by examining the same women over time, using data from the Young Women's cohort of the National Longitudinal Surveys. Two groups of women were studied: those who were aged 29-33 in 1978 and those who were 29-33 in 1983. The labor force transitions of the two groups were compared over a 5-year period. Some of the findings of the study were as follows: (1) in 1978, 62.2 percent of the women in the sample age were in the labor force--62.5 percent of them worked full time, 31 percent worked part time, and 6 percent were unemployed; (2) by 1983, the labor force participation rate increased to 73 percent--59 percent worked full time, 35 percent part time, and 6 percent were unemployed; (3) about three-fourths of those who worked full-time in 1978 were full-time workers in 1983, and half of the part-timers in 1978 were full-time workers in 1983; (4) most of the women who moved out of part-time work during the 5-year period moved into full-time work; (5) of those who were not in the labor force in 1978, nearly half were in the labor force in 1983, most working part-time; (6) in 1988, labor force participation increased to 80 percent, with 69 percent working full-time and 28 percent part-time; (7) for both groups, labor market status remained fairly stable over 5 years, with three-quarters of the women remaining in full-time work; (8) women who were married and worked part-time in 1978 but were no longer married in in 1983 were more likely to work full-time in 1983; (9) women who were not married in 1978 and got married by 1983 were even more likely to work full-time in 1983; (10) among women who added a child between 1978 and 1983, more moved into full-time work (37 percent) than dropped out of the labor force (15 percent); and (11) women who had a child age 5 or under in the household in both 1978 and 1983 were the most likely to remain as part-time workers. The study concluded that transitions from part-time work are only very loosely tied to changes in the presence of a young child. (KC)