The current industrialized world and ever advancing technology has changed human life by a significant increase in the level of stress and anxiety. Nurses are among those professionals who experience an overwhelming level of stress, anxiety and depression due to work overload and subsequent burnout. The nature of nursing profession for a vulnerable human character increases the possibility of emotional setbacks. Hence, this study was designed to explore and identify the prevalence of anxiety, stress and depression among the Iranian nurses and investigate how these variables relate to personal characteristics and influence the quality of patient care. Using a correlational descriptive design and random cluster method, 242 nurses who worked at different hospital wards in Tabriz, Iran were assessed for anxiety, stress and depression, while their personal characteristics were identified. Data were collected by using a standard questionnaire for stress, anxiety and depression (DASS-21) and later analyzed by SPSS (ver.17).Results showed that Iranian nurses suffered from a moderate level of anxiety, stress and depression and gender influenced these variable rates (p<0.05). Hospital ward type had a relation with stress level (p<0.05), being interested in nursing had an inverse relation to anxiety, stress and depression (p<0.05), while the education level positively related to depression rate among nurses (p<0.05). Type of work at different shifts influenced stress (p<0.05) and marital status reduced depression among nurses (p<0.05). Prevalence of stress and anxiety among the Iranian nurses were at a significant level with susceptibility to experience psychological disorders and provide lower quality of patient care. Findings of this study can alarm the Iranian authorities in healthcare systems to adopt a new policy and improve the current state of health for nurses and patients.