Serial changes in urinary catecholamine excretion were determined for 17 cockpit crews (6 captains, 6 copilots and 5 flight engineers) of JASDF C-1 aircraft during 10-hour (h) scheduled flights, in which captains and copilots performed almost the same flight tasks. The norepinephrine/epinephrine ratio (N/E) in copilots decreased significantly during the flight, whereas little decrease of the N/E was found in captains. Flight engineers showed an intermediate N/E value between captains and copilots. Hormonal responses appeared to correlate with differences in the amount of flying experience of crewmembers. Differences between captains and copilots were more significant when handling the aircraft. Results suggested that flight stresses perceived by crewmembers in the same cockpit were influenced by their flying experience and flight position which could be clearly assessed by determining relative excretions of epinephrine and norepinephrine.