INTRODUCTION: There has been interest in using human blood products in nonhuman primate models of trauma to supplement human studies and to provide evidence to guide novel trauma resuscitation strategies. The compatibility of human RBCs has not been extensively studied in nonhuman primate species. METHODS: Whole blood samples were collected from five healthy, nontransfused, not previously pregnant Chinese-bred rhesus macaques. The whole blood was centrifuged, and the plasma was decanted from each sample. Group O-negative human RBCs were mixed with the plasma from the rhesus macaque monkeys. Compatibility testing was performed by an immediate spin test and polyspecific and monospecific anti-human globulin (AHG) tests in glass tubes. RESULTS: Immediate spin testing revealed three out of five plasma samples (60%) from rhesus macaques caused at least 1+ agglutination with the human RBCs. Polyspecific anti-human globulin (AHG) tests demonstrated that two of five plasma samples (40%) from rhesus macaques caused at least 1+ agglutination with the human RBC, while the monospecific AHG testing revealed that the incompatibility was caused by C3d, not IgG. CONCLUSION: Human RBCs are not compatible with the plasma of some, but not all, Chinese-bred rhesus macaques.