The present study aims to estimate the treated prevalence of Acute and Transient Psychotic Disorders (ATPD) among psychiatric inpatients and to identify its distinguishing clinico-demographic features. All consecutive ATPD patients admitted to the psychiatric ward of King Fahd Hospital at the University, Al-Khobar, Saudi Arabia over 14 years (1988-2002) constituted the study group. A control group of an equal size, matched for sex and age, was randomly drawn from all the other psychiatric patients admitted during the same period. The sociodemographic and clinical features of the two groups were compared. ATPD was diagnosed in 148 (7.3 percent) of a total of 2024 patients, and in 14.1 percent of the 1047 patients presenting with psychotic symptoms. Compared to the matched control group, the ATPD patients were significantly more frequently Asian expatriates, unskilled workers recently immigrating, unaccompanied by their families, living with work-mates or employers. In the overwhelming majority (89.2 percent) of cases ATPD arose following identifiable stressful life events. The bulk of ATPD cases seem to be psychogenic reactions to upsetting psychosocial stressors in a background of inadequate social support.