We evaluated the use of the gas exchange rate as an ecologically relevant indicator of chemical stress in avian embryos/eggs. Northern bobwhite quail (Colinus virginianus) were exposed to octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) via feed containing nominal concentrations of 0, 12.5, 50.0, and 125.0 mg kg-1. Metabolic rates (oxygen consumption) of developing quail eggs were then measured via respirometry to examine potential effects of HMX exposure. Metabolic rates were examined on 5, 9, and 21 d of incubation. Next, concentrations of HMX in embryos/eggs were determined by liquid chromatography-mass spectrometry. Mean (±SE) concentrations of HMX in eggs were 21.0 ± 5.9, 1113 ± 79.0, 3864 ± 154.0, and 7426 ± 301.1 ng g-1 in control, low, medium and high dose groups, respectively. There were significant differences in oxygen consumption among the three embryo ages, however differences among the ages were not consistent among dose groups (age x dose group interaction p < 0.0001). Oxygen consumption rates did not vary as a function of HMX in embryos (p = 0.18). No evidence was observed for alterations of in ovo metabolic rates associated with HMX exposure. © 2008 Elsevier Ltd. All rights reserved.