Persons engaged in special occupations rely heavily on the vestibular system for spatial orientation under non-terrestrial conditions. These include professional divers, aircraft pilots, and seamen. Vestibular symptoms in these populations might result from the entire known spectrum of inner ear diseases. In addition, disequilibrium, vertigo, hearing loss and autonomic symptoms might stem from the specific conditions to which such individuals are exposed. Inner ear barotrauma, inner ear decompression sickness, motion sickness, and mal de debarquement are discussed with special reference to the use of various vestibular function tests for patient diagnosis and management. Professional divers and aircraft pilots may be subjected to rapid and large changes in ambient pressure with increased risk to previously damaged vestibular and cochlear systems. Spatial disorientation and acute vertigo represent a life-threatening hazard, not only for the submersed diver and the pilot flying a sophisticated aircraft, but also for other people dependent on their abilities, such as diving companions or airline passengers. On the other hand, significant consideration should be given to the high investment on the part of the individual and society in such highly professional careers. The role of vestibular testing in the evaluation and follow-up of such patients and the decision about compatibility with a highly demanding profession are discussed.