Hypothermia prior to and/or during no-flow ischemia promotes cardiac functional recovery and maintains mRNA expression for stress proteins and mitochondrial membrane proteins (MMP) during reperfusion. The adaptation and protection may occur through cold induced change in anaerobic metabolism. Accordingly, the principal objective of this study was to test the hypothesis that hypothermia preserves myocardial function during hypoxia and reoxygenation. Hypoxic conditions in these experiments were created by reducing oxygen concentration in perfusate, thereby maintaining or elevating coronary flow (CF). Isolated Langendorff perfused rabbit hearts were subjected to perfusate (PO₂=38 mmHg ) with glucose (11.5 mM) and perfusion pressure (90 mmHg). Control group (C) was at 37°C for 30 min prior to and 45 min during hypoxia, while hypothermia group (H) was at 29.5°C for 30 min prior to and 45 min during hypoxia. Re-oxygenation occurred at 37°C for 45 min for both groups. CF increased during hypoxia. Hypothermia markedly improved functional recovery during re-oxygenation, including left ventricular developed pressure (DP), the product of DP and heart rate (PRP), dP/dt_max, and oxygen consumption (MVO₂) (P < 0.05 vs C). MVO₂ decreased during hypothermia. Lactate and CO₂ gradients across the coronary bed were the same in C and H during hypoxia implying similar anaerobic metabolic rates. Hypothermia preserved MMP F₁-ATPase mRNA levels, but did not alter adenine nucleotide translocator-1 or heat shock protein-70 mRNA levels. In conclusion, hypothermia preserves cardiac function after hypoxia in the hypoxic high coronary flow model. Thus, hypothermic protection does not occur exclusively through cold-induced alterations in anaerobic metabolism.