This study examines how mass migration from the former Soviet Union to Israel affected natives' probability of moving from employment to non-employment and vice-versa. Using 1989-99 data from the Israeli Labor Force Survey, the authors find that the share of immigrants in labor market cells defined by occupation, industry, district of residence, schooling, and experience was generally positively associated with natives' probability of moving from employment to non-employment. However, when the analysis controls for the endogenous sorting of immigrants across cells, this effect is substantially reduced for men, and disappears or is even reversed for women. The authors conclude that immigrants tended to cluster in labor market cells with high turnover rates and that immigration did not increase natives' likelihood of exiting employment. They also find no discernible effects of immigration on natives' transitions between labor market cells or on the probability of their moving from non-employment to employment.