Clinical pathology is routinely used to diagnose and monitor response to disease. In this study the hematologic response of red-eared slider turtles (Trachemys scripta elegans) to experimental ranavirus infection was measured during two separate environmental temperature trials. Blood samples were collected from six red-eared sliders experimentally infected with a ranavirus, frog virus 3-like virus (FV3-like), and from 10 uninfected turtles twice weekly for 30 days postinfection to evaluate several hematologic variables. There were no significant changes in packed cell volume, white blood cell (WBC) count, or WBC differential counts over time in either the infected or uninfected groups. There were significant increases in WBC in infected turtles on days 18 and 22 postinoculation (22°C; 71.6°F) and on days 8 and 11 (28°C; 82.4°F) compared to uninfected turtles. Total solids were significantly decreased (P = 0.034) over time in the red-eared sliders infected with FV3-like virus regardless of temperature. Intracytoplasmic inclusions were seen in two red-eared sliders and only in animals in the 22°C (71.6°F) temperature trial. The hematologic findings from this study suggest that closely monitoring an animal during the early stages of infection may reveal some mild changes in the WBC count; however, serial sampling would be necessary to detect these small differences. Further work utilizing larger sample sizes and more-frequent sampling are needed to determine the clinical significance of the hematologic response of chelonians to this devastating virus.