To determine the acute effect of reduced barometric pressure and hypoxia on renal nerve activity, urethane‐anaesthetized and mechanically ventilated rabbits were randomly exposed to the following four separate conditions in a decompression chamber: hypoxic hypoharia (n=71, hypoxic normobaria (n= 5), normoxic hypoharia (n= 8) and slow normoxic hypobaria (n= 7). A combination of rapid decompression and simultaneous adjustment of inspiredPO2was used to simulate an altitude of 6600 m, and renal nerve activity and haemodynamics, such as systemic blood pressure and heart rate, were measured. During both hypoxic hypobaria and hypoxic normobaria, there were significant and similar increases in renal nerve activity at 6600 m (54 ± 7% and 61 ± 13% from each baseline, respectively). However, there were no changes in renal nerve activity during normoxic hypoharia or slow normoxic hypoharia with decompression rates of 1000 or 400 m min‐l, respectively. From these results, we conclude that a reduction in barometric pressure without hypoxia does not affect renal nerve activity in anaesthetized ra