The purpose of this research was to study traumatic and dissociative experiences in a sample of Spanish patients with psychosis and their relationship to hallucinations. Seventy-one patients with psychosis filled in a dissociative experiences scale (DES-II, Carlson & Putnam, 1993), a trauma questionnaire (TQ, Davidson, Hughes, & Blazer, 1990) and the PANSS delusion and hallucination items (Kay, Opler, & Lindenmayer, 1988). The results showed that subjects who had hallucinations and delusions had undergone a significantly larger number of traumatic experiences in childhood, but not as adults. Subjects with hallucinations and delusions had higher scores in dissociation than those who did not have these psychotic symptoms. It was also found that subjects with hallucinations had had experienced more physical abuse and threats in childhood, while there were no differences in the type of trauma for presence or not of delusions. Finally, of the factors studied in this research, only depersonalization predicted the presence of hallucinations, and none of these factors predicted the presence of delusions.