Childbirth is a unique experience in women's life. Various factors including human and non-human environment are involved in shaping the experience of childbirth.This study investigated the role of the environment on the psychological birth trauma from the perceptions of Iranian mothers. A qualitative descriptive study was conducted from September 2011 to February 2012, using audiotaped interviews with 23 Iranian women recruited from Tehran and Isfahan. The interviews were transcribed verbatim and analysed using the content analysis. Two themes were extracted from the data: human and non-human environment; and several categories also emerged from the data, which are communication with mother, awareness of mother's needs, support for mother, medical clinical competence, professional responsibility, hospital's physical structure, hospital's equipment, routine care in hospital and rules governing the hospital's environment, respectively. Considering the significant role of environment in psychological birth trauma of the mother, an appropriate intervention must be developed to enhance both human and non-human environment in order to reduce the psychological birth trauma.