In this paper we examine the circumstances and determinants of female migra
tion between Mexico and the United States. Using data from the Mexican Migr
ation Project, we considered the relative timing of males' and females' mov
es northward. We then estimated legit and probit models to study the determ
inants of male and female out-migration; among women we also estimated a mu
ltinomial legit model to uncover differences in the process of migration fo
r work versus not for work. We found that women almost always followed othe
r family members, either the husband or a parent; only a tiny minority init
iated migration independently. Although males also are quite likely to be i
ntroduced to migration by a parent, nearly half of all male migrants left f
or the United States before or without a wife or a parent. Estimates of the
determinants of migration suggested that males move for employment, wherea
s wives generally are motivated by family reasons. Daughters, however, disp
lay a greater propensity to move for work, and the determinants of their wo
rk-related moves closely re semble those of sons and fathers.