The effects of gas composition and temperature on both the O2 consumption (RRO2) and CO2 production (RRCO2) rates of `Red Gold' nectarines were investigated. Three temperatures (0, 10, and 20 °C) and six gas combinations of initial O2 (1%, 5%, and 20%) and CO2 (0 and 15%) with the balance N2 were used. Triplicate glass jars containing two fruits each were flushed with the respective certified gas mixtures and stored in environmental chambers maintained at 0, 10, and 20 °C. Head space O2 and CO2 concentrations were monitored until O2 levels dropped to 1% or less. Both RRO2 and RRCO2 showed significant increases (P < 0.05) as temperature increased from 0 to 20 °C at the gas concentrations tested. The RRO2 increased slightly (P < 0.05) as initial O2 concentration increased while showing no changes at the range of initial CO2 concentrations used in the study. For RRCO2, no significant changes (P < 0.05) were observed as gas concentrations varied at constant temperatures. This information is useful in establishing empirical models for modified atmosphere packaging predictions.