This article examines the patterns of communication of American Indians in Ok­lahoma, whose activities are closely interfaced with those of non-Indians. Given the highly integrated macro-social milieu, and based on Kim's (1988,1995a, 1995b, in press) communication theory of cross-cultural adaptation, the present analysis addresses the extent to which American Indians in Oklahoma are com­municatively engaged within and outside the Indian community and the nature
o f the relationship between these two types of communication activities and psy­chological and functional integration into the mainstream society. The analysis utilizes portions of the quantitative data obtained through 182 one-on-one inter­ views during 1988-1989 at six research sites in the state. Interethnic and inter­ ethnic communication activities are measured by five indicators: (a) ingroup and outgroup perception; (b) casual interpersonal relationships; (c) intimate interper­sonal relationships; (d) participation in community organizations; (e) use of mass media. Results show that as a group the Oklahoma Indians are active in both in­terethnic and interethnic communication, reflecting the highly integrated macro­ environment of the State of Oklahoma. Those who are more actively engaged intraethnic communication are found also to be more active in interethnic commu­nication. Results further suggest that both interethnic and interethnic communi­ cation activities of Oklahoma Indians are linked positively to their integration into the mainstream socio-cultural milieu. Compared with intraethnic communica­tion, interethnic communication appears to play a more potent role infacili­tating the integration process.