A weaker Sami cultural orientation reflected by favoring assimilation is associated with current drinking patterns among young indigenous Sami longitudinally. Smoking was associated with strong ethnic group identification in late adolescence, but predicted by assimilation in young adulthood. Apparently, Sami in late adolescence have, at least partially, adopted the substance use of the contextual majority in which they reside. The preventive impact of a stronger ethnic identity and ethnic supportive environments is only noted in late adolescence. Prior studies have indicated similar smoking rates among young Sami, but less alcohol use than their non-Sami peers (Spein et al, 2002, 2006).The Sami are the indigenous people of northern Scandinavia and the Russian Kola Peninsula. The Sami have their own culture, language, and their own religion. This study explored the cross-sectional and prospective influence of ethno-cultural factors on (1) current drinking and smoking among Sami through late adolescence and young adulthood and (2) adolescents’ prospective perceptions of own drinking in young adulthood. It is hypothesized that Sami individuals with weaker Sami cultural ties, a lack of ethnic identity and/or group identification, and strong national group identification, would report more substance use. The overall study sample included a subsample of 675 15 to 19 year old indigenous Sami. Tables, references