Thanatology is the academic study of dying, death and grief. It encompasses thoughts, feelings, attitudes, events and the psychological mechanisms of dealing with them. Death obsession includes ruminations, repetitive, intrusive thoughts or images about death. Death obsession in the nursing profession can occur on a daily basis, and communication with dying patients can be stressful for nurses. Nurses with such emotion need to death education program. Didactic method is one of the approaches to death education program. Aim of this study was the effectiveness of didactic approach on the reduction of death obsession among nurses. The participants were 12 nurses. They were selected randomly from ICU and CCU wards of the Khatom-Al-Anbia General Hospital in Tehran city. The nurses completed the Death Obsession Scale (DOS) before and after intervention. Didactic approach was held in 36 hours in 6 workshops weekly. Data were analyzed through dependent t-test using SPSS/WIN 16.0 program. Results showed that there was a significant difference between pretest and posttest for the didactic approach on the DOS scores (T=2.21, df=11, p<.05). We conclude that didactic approach is useful on the reduction of death obsession and promotion of mental health in the nurses. It is recommended that in psychoeducational interventions related to attitudes towards death and dying, the focus should be placed on a community-based approach.