Prior research seeking to explain variation in extended family coresidence focused heavily on the potentially competing roles of cultural preferences and socioeconomic and demographic structural constraints. We focus on challenges associated with international immigration as an additional factor driving variation across groups. Using 2000 census data from Mexico and the United States, we compare the prevalence and age patterns of various types of extended family and non-kin living arrangements among Mexican-origin immigrants and nonimmigrants on both sides of the U.S.-Mexico border. Additionally, we use the Survey of Income and Program Participation to examine the stability of extended family living arrangements among Mexican-origin immigrants and natives in the United States. We find that newly arrived immigrants to the United States display unique patterns in the composition and stability of their households relative to nonimmigrants in both Mexico and the United States. Recent immigrants are more likely to reside in an extended family or non-kin household, and among those living with relatives, recent immigrants are more likely to live with extended family from a similar generation (such as siblings and cousins). Further, these households experience high levels of turnover. The results suggest that the high levels of coresidence observed among recently arrived Mexican immigrants represent a departure from “traditional” household/family structures in Mexico and are related to the challenges associated with international migration.