Cynomolgus macaques (Macaca fascicularis) are increasingly being used for a wide variety of studies, including anticoagulant therapy development and toxicology testing. Cynomoglus macaques are sourced from several different countries, some have indigenous populations and some have established breeding colonies from unknown indigenous populations. Genetic monitoring can verify the source of the macaques but is not usually included in study group monitoring. Small study group numbers and heterogeneous groups of animals can create difficulty in statistical interpretation of study results. The present study compares coagulation responses from animals attributed to sources in Vietnam, Cambodia, Philippines, Indonesia, China and Mauritius. Genetic characterization of 12 microsatellite loci used a Beckman/Coulter capillary electrophoresis system to determine genotypes. The baseline clotting profile was evaluated by determination of prothrombin time (PT), activated partial thromboplastin time (aPTT), common pathway (Heptest®), and thrombin time (TT). Blood was drawn and stored in EDTA for genetic analysis or immediately transferred to sodium citrate tubes, centrifuged to obtain plasma and stored at ‐80oC. Clotting tests were performed using the ACL 300+ and BBL Fibro System manual fibrometers. Statistical analysis for heterogeneity were performed with the groups of animals by their attributed source and reanalyzed after regrouping by genetic data. The heterogeneity was highly significant when the groups were evaluated based only on their attributed source, but was not significant when assigned to groups based on genetic characterization. The animals sourced from Mauritius were consistently more homogenous when compared to the other sources.A clear understanding of the genetic background can insure group consistency and is essential when applying specific statistical tests to interpret data.