The 2-p-domains potassium channel TASK1 is expressed in carotid bodies and in brainstem regions involved in the control of respiration. It has been suggested that TASK1 channels play a role for oxygen sensing in chemoreceptors. This study was aimed at investigating the respiratory phenotype of TASK1 knockout mice using whole body plethysmography. In female mice, the respiratory response upon hypoxia was not different between the genotypes. Male TASK1 -/- mice, however, had increased values for minute volume, mainly due to an enhanced tidal volume. The pattern of the respiratory response upon 10% oxygen was qualitatively similar to +/+ mice with an immediate increase of respiration followed by alkalosis-induced depression and recovery from depression after 6-8 h. Also during hypercapnia (5% CO2), male TASK1 -/- mice showed a stronger stimulation of respiration, mainly due to an increased tidal volume. In conclusion, TASK1 inactivation leads to enhanced respiratory responses towards hypoxia and hypercapnia in male but not in female mice. These data suggest that TASK1 channels participate in the regulation of respiration. Interestingly, the loss of TASK1 concerning oxygen sensing can be compensated by other mechanisms since oxygen sensing is preserved in TASK1 -/- mice.