Biochemical panels were analyzed on 181 individual free-ranging white rhinoceros (Ceratotherium simum) from Kruger National Park, South Africa. These animals were immobilized between July 2006 and May 2010 for management purposes. Serum and heparinized plasma samples were analyzed using an in-house chemistry analyser (ABAXIS VetScan2). The objectives of this study were to establish biochemical references ranges for Kruger National Park's population of white rhinoceros; to assess differences in values obtained using sera or plasma; and to assess differences in values between gender and different age categories. Significant differences between plasma and serum values were found in most measured parameters except minerals (calcium and magnesium). Because all animals appeared clinically healthy at the time of blood collection, it is hypothesized that choice of anticoagulant may affect certain parameters. Comparison between age categories and gender also resulted in significant differences in a few measured parameters. Identifying differences are important when establishing baseline reference ranges for wildlife populations to allow accurate monitoring of trends that may change over time. The paucity of data on normal biochemical ranges for free-ranging white rhinoceros demonstrates the value of this study and importance of evaluating potential confounding variables.