The Yanomama Indians are a tribe of slash-and-burn cultivators who live deep in the tropical forests of southern Venezuela and northern Brazil. As a part of a larger study of microdifferentiation and gene flow we report the results of genetic typing of the haptoglobin (Hp), transferrin (Tf), Group Specific Component (Gc), albumin (Alb), ceruloplasmin (Cp) and two beta lipoprotein (Ag and Lp) systems in Yanomama Indians from 37 villages, each with 31 t o 176 sampled individuals. The findings in several villages in which fewer than 30 individuals were sampled have been grouped together in a ‘miscellaneous’ category. The total number of persons typed for each system ranges between 359 (Ag system) and 2503 (Gc system). A report listing preliminary gene frequencies for the first ten of these villages has been previously prepared (Arends et al. 1967). The location of the villages and a description of the dates and techniques of blood collection and transport are given in Gershowitz et al. (1972) and Ward (1972).