People experiencing sensory deprivation often report perceptual disturbances such as hallucinations, especially over extended periods of time. However, there is little evidence concerning short-term sensory deprivation and whether its effects differ depending on the individual concerned, and in particular their proneness to psychosis. This study explored whether perceptual disturbances could be elicited by a brief period of complete isolation from sound and vision in both highly hallucination prone and nonhallucination prone groups. Greater psychotomimetic experiences taking the form of perceptual disturbances, paranoia, and anhedonia were found across both groups when under sensory deprivation. In addition, hallucination-prone individuals experienced more perceptual disturbances when placed in short-term sensory deprivation than nonprone individuals. This result is discussed in terms of difficulties in source monitoring as a possible mechanism involved in proneness to hallucinations.