Galvanic vestibular stimulation (GVS) is known to create an imbalance in the vestibular inputs, thus it is possible that the simultaneously applied GVS obscures adequate gravity-based inputs to the vestibular organs or modifies an input-output relationship of the vestibular system, and then impairs the vestibular-mediated response. To examine this, arterial pressure (AP) response to gravitational change was examined in conscious rats with and without GVS. Free drop-induced microgravity and centrifugation-induced hypergravity were employed to elicit vestibular-mediated AP response. GVS itself induced pressor response in an intensity dependent manner. This pressor response was completely abolished by vestibular lesion, suggesting that the GVS-induced response was mediated by vestibular system. The pressor response to microgravity (35 ± 3 mmHg) was significantly reduced by simultaneously applied GVS (19 ± 1 mmHg) and pressor response to 3 G load was also significantly reduced by GVS. However, GVS had no effect on air jet-induced pressor response. The effects of GVS on pressor response to gravitational change were qualitatively and quantitatively similar to that caused by the vestibular lesion, of which effects were demonstrated in our previous studies (11, 18, 25). These results indicate that GVS reduced vestibular-mediated pressor response to gravitational change, but has no effect on the nonvestibular-mediated pressor response. Thus, GVS might be employed for the acute interruption of AP response to gravitational change.