Objectives-The aim of the present study is to describe variations in blood glucose concentrations depending on their clinical diagnosis in a large cohort of chelonians. Methods-Of the 967 eligible client owned chelonians, data on species, sex, habitat, blood glucose, appetite, organ category, and disease type data were extracted and analyzed using commercial statistical software. Chelonians could fit in more than one category for both organ system and type of disease, and categories with less than ten individuals were excluded from analysis. Results-Mean blood glucose concentrations based on organ category were as follows: cardiovascular (72.5 mg/dL; n=20), endocrine (85.5 mg/dL; n=468), gastrointestinal (92.5 mg/dL; n=236), musculoskeletal (86.0 mg/dL; n=113), no organ identified (95.0 mg/dL; n=30), ophthalmic (83.0 mg/dL; n=23), reproductive (94.0 mg/dL; n=299), respiratory (91 mg/dL; n=167), integument (84.0 mg/dL; n=138), and urinary (95.0 mg/dL; n=298). Based on the results of a generalized linear mixed model, compared to chelonians with urinary conditions, all other categories of organs affected had significantly lower glucose concentrations (all P<0.05). Mean blood glucose concentrations based on disease type were as follows: infectious (86.0 mg/dL; n=404), inflammatory (84.0 mg/dL; n=59), metabolic (89 mg/dL; n=728), neoplastic (89.0 mg/dL; n=25), no specified disease (92.0 mg/dL; n=42), traumatic (102.0 mg/dL; n=87), and vascular (77.5 mg/dL; n=32). Compared to chelonians affected by trauma, all other disease type except inflammatory had lower blood glucose concentrations (all P<0.05). Conclusions-Blood glucose concentrations may vary in chelonian patients depending on the type of disease and the organ affected.