Twenty-three lizards were captured for this study, both males and females (12 males, 10 females, 1 undetermined), with a large range in body weights (40–286 g) appeared to be healthy based on activity level, physical examinations, and body condition scores. Heparinized blood samples from 20 free-ranging basilisk lizards (Basiliscus plumifrons) in Costa Rica were used for determining complete blood cell counts, plasma, and heparinized whole blood biochemical analysis. This information will serve as baseline reference data for future health assessment studies of free-ranging and captive basilisk lizards, as well as epidemiologic, conservation, and captive-breeding studies. A point-of-care analyzer was useful for this field study, and clinical chemistry values from heparinized whole blood samples were similar to values from plasma, which indicates that separation of plasma may not be necessary to process blood samples on site in remote areas. To the authors' knowledge, this is the first report of hematologic and plasma biochemical data from free-ranging B. plumifrons.