Hypoxic Pulmonary Vasoconstriction (HPV) is known to effect regional pulmonary blood flow distribution. It is unknown whether lungs with well-matched ventilation (V_A)/perfusion (Q) have regional differences in the HPV response. Five prone pigs were anesthetized and mechanically ventilated (PEEP = 2 cm H₂0). Two hypoxic preconditions (F_IO₂ = 0.13) were completed to stabilize the animal's hypoxic response. Regional pulmonary blood flow and ventilation distribution was determined at various F_IO₂'s (0.21, 0.15, 0.13, 0.11, 0.09) using the fluorescent microsphere technique. Q and V_A in the lungs were quantified within 2 cm³ lung pieces. Pieces were grouped, or clustered, based on the changes in blood flow when subjected to increasing hypoxia. Unique patterns of Q response to hypoxia were seen within and across animals. The three main patterns (clusters) showed little initial difference in V_A/Q matching at room air where the mean V_A/Q range was 0.92 to 1.06. The clusters were spatially located: in cranial, central and caudal portions of the lung. With decreasing F_IO₂, blood flow shifted from the cranial to caudal regions. We determined that pulmonary blood flow changes, caused by HPV, produced distinct response patterns that were seen in similar regions across our prone porcine model.