The Middle East is underrepresented in psychosis research. The ARAS recent onset acute phase psychosis survey (ARAS) is a longitudinal cohort across multiple centers in Iran, established to investigate characteristics, determinants and early course of psychosis in a non-Western, Middle East context. Here, baseline characteristics of the ARAS cohort are reported. The ARAS cohort enrolled patients with recent onset psychosis from September 2018 to September 2021 in East Azerbaijan, Kermanshah and Tehran, including Iranian patients from different sociocultural contexts. The baseline assessment included demographics, socioeconomic status, clinical (positive, negative, depressive symptoms) and psychosocial (religiosity, social support, self-stigma) characteristics, cognitive functioning, metabolic profile, substance use and medication use measured by validated questionnaires. These assessments will be followed up after one and five years. A total of 500 patients with a first episode of psychosis were enrolled from three provinces in Iran. With 74.1% being male, the mean age (SD) of patients was 32.3 (9.7) years. Nearly a quarter of patients was diagnosed with schizophrenia and 36.8% with substance induced psychotic disorder. Amphetamine (24%) and opium (12%) use were common, cannabis use was not (5%). Only 6.1% of patients lived alone while 29% of patients was married and had children. The majority of them had achieved secondary educational level and 34% had a paid job. The most common antipsychotic treatment was risperidone. There was a wide range for scores of PANSS, with 9.4% having dominant negative symptoms. The most common prescribed medication was risperidone. Near to 40% of patients had noticeable signs of depression and prevalence of metabolic syndrome was 13.4%. The majority of patients (57.2%) had moderate and 5.4% reported to have severe disability. More than 30% reported to be highly religious. Patients had the highest satisfaction with people living with, and the lowest for finance and job.