CONTEXT: Levels of modern contraceptive knowledge and use among people living in rural areas of Guatemala differ substantially from those of people living in urban areas. Understanding the pace and extent of rural-to-urban mi- grants' adoption of urban contraceptive practices is important in determining if there is a strong need for migrant-fo- cused reproductive health programs. METHODS: Bivariate and multivariate analyses of data on 971 married male and female respondents in the 1999 Guatemalan Migration and Reproductive Health Survey were used to examine how migration status and duration of residence in an urban area are associated with knowledge of modern contraceptive methods and current contracep- tive use. RESULTS: Migrants' contraceptive knowledge was positively associated with the number of years they had lived in an urban area. Mayan migrants in Guatemala City did not accumulate contraceptive knowledge at the same rate as non- Mayan migrants, perhaps due to cultural and linguistic barriers to obtaining knowledge of and access to contracep- tives. Rural-to-urban migrants eventually achieve a level of modern contraceptive use slightly below that of urban nonmigrants, with the level of contraceptive knowledge being an important factor associated with use of modern methods.