BACKGROUND The influence of expressed emotion (EE) on the course of the schizophrenia has been studied in different countries. Cultural influence on the level of EE has shown the importance of examination of EE in different cultures. The present study examined the distribution of components of EE and influence of EE on the course of schizophrenia in Iran. METHODS Two psychiatric centers from two dissimilar cities, Tehran and Hamedan, were chosen. Seventy-eight patients who suffered from schizophrenia based on the diagnostic criteria of DSM-III-R were selected. Interviews with 97 key family members were conducted using the Camberwell Family Interview. Psychiatrists who were blind to the EE status of the family household evaluated patients' symptoms based on a cohort study design during the 9-months follow-up. RESULTS Sixty percent of the patients were living in a high EE household. The relapse rate in the high EE group was higher, but did not reach statistical significance. However, male patients as well as chronic patients were significantly more likely to relapse in the high EE group (P = 0.05). CONCLUSIONS The results suggested that high EE is a risk factor on the course of schizophrenia in Iran. The distribution of the components of EE showed differences compared to other cross-cultural studies. The results of this study can be used in planning appropriate psychoeducational programs for families of patients in Iran and culturally similar populations.