A sample of 121 Piaroa Indians from the Federal Amazonia Territory (Venezuela) was studied for the following serum protein polymorphisms: haptoglobin (HP), group-specific component subtypes (GC), orosomucoid (ORM), third component of complement (C3), transferrin C subtypes (TF) and α1-antitrypsin subtypes (PI). The gene frequencies in the whole sample were: HP1 = 0.821; GC1S = 0.698; GC1F = 0.058; GC2 = 0.244; ORMS = 0.434; C3S = 0.699; C3F = 0.289; C3var = 0.012; TFC1 = 0.955; PIM1 = 0.467; PIM2 = 0.004; PIM3 = 0.529. The studied Piaroa sample came from three different communities: Gavi-lan, Paria and Alto Carinagua. The distribution of GC, C3 and HP polymorphisms was heterogenous within the three groups. All the examined serum protein markers were polymorphic, in contrast to some enzymatic markers (ADA, DIA, 6PGD, AK) previously studied, which were shown to be monomorphic in the Piaroa. The results were compared with data from other populations living in the same territory