This study examines the transition to first union among Puerto Rican w
omen. I argue that understanding the behavior of mainland Puerto Rican
s requires attention to family patterns in Puerto Rico and to the dyna
mics of migration between Puerto Rico and the United States. The study
therefore is based on pooled data from comparable surveys undertaken
in the two settings. These data allow for event history analyses that
compare the union formation behavior of migrants with that of nonmigra
nts, and consider the role of migration in producing the observed unio
n patterns. Multivariate models show that migrants are more likely tha
n nonmigrants to form unions early and to enter informal unions. Addit
ional analyses show that selective migration plays a role in producing
this pattern. Overall the findings demonstrate the importance of usin
g data from both origin and destination locales for understanding the
behavior of migrant groups.