Hematology, plasma biochemistry, and blood gas analysis were performed on venous samples obtained from free-ranging Eastern Copperheads (Agkistrodon contortrix) and Eastern Ratsnakes (Pantherophis alleghaniensis) in central North Carolina during a mark-recapture study conducted from April to October 2015 at the North Carolina Zoo. Blood samples were collected from 31 (15 male and 16 female) free-ranging copperheads and 34 (20 male and 14 female) free-ranging ratsnakes at the beginning and end of restraint. Restraint was performed for morphometric measurements, sex determination, and identification via placement of intracelomic passive integrated transponder (PIT) tags and marking of ventral scutes with a handheld electrocautery unit. Blood gas analytes were measured at the beginning of restraint and compared to analytes measured at the end to evaluate for changes secondary to handling. Total restraint time prior to the first blood sampling was 1.4 ± 0.4 mins (mean ± SD) and 1.0 ± 0.2 mins (mean ± SD) and restraint time prior to second blood sampling was 12.5 ± 2.4 mins (mean ± SD) and 13.5 ± 3.4 mins (mean ± SD) for copperheads and ratsnakes, respectively. Blood lactate concentrations at the beginning of restraint were similar for both species. Lactate concentrations increased significantly and pH decreased significantly for both species at the end of restraint when compared to the beginning of restraint. Furthermore, lactate concentrations at the end of restraint were significantly elevated in ratsnakes compared to copperheads. This study provides guidelines for interpretation of venous hematology, plasma biochemistry, and blood gas values for free-ranging copperheads and ratsnakes in central North Carolina and demonstrates the physiological response to venous blood gas analytes secondary to capture and restraint.