Biochemical reference range values were determined for 91 clinically healthy Arabian sand gazelle, reem (Gazella subgutturosa marica), and 66 Arabian mountain gazelle, idmi, (Gazella gazella) kept in captivity. Parameters investigated included: albumin (ALB), alkaline phosphatase (ALP), alanine transaminase (ALT), amylase (AMY), total bilirubin (TBIL), blood urea nitrogen, calcium (Ca), phosphorus (PHOS), creatinine (CREAT), glucose (GLU), sodium (Na), potassium (K), total protein (TP) and globulin (GLOB). Specific and interspecific differences related to sex and age were investigated. In reem gazelles there were significant differences between adults and juveniles of both sexes in the levels of all parameters investigated except for TBIL, GLU and K. Unlike in reem gazelles, idmi gazelles showed no significant differences in the levels of ALB, ALT, TBIL, PHOS, Ca, Na and GLU between both sexes and age groups. Adult reem and idmi gazelles exhibited significant differences in the levels of ALB, ALP, ALT, AMY, CREAT, GLU, K, TP and GLOB compared to juveniles of both species.