Abstract : Communication serves as the foundation for the connection between a nurse and patient and is a crucial component of trust and comfort. Nurses working in the critical care units (CCU) face especial challenges when communicate with unconscious ill, mechanically ventilated or sedated patients. Communication between these patients and nurses needs specific skill of commitment, and knowledge. To evaluate the intensive care unit nurses knowledge related to educational program constricted for communication with patients undergoing mechanical ventilation as a nursing competence. A quantitative study quasi-experimental design was used with the application of pre, and posttest to achieve the study objectives which directed to evaluate the Effectiveness of Patient Communication Skills for Patients Undergoing Mechanical Ventilation Educational Program on the Intensive Care Unit Nurses Knowledge started from 9 January to 27 May 2022. The study conduct at the intensive care units at Al- Hilla Teaching Hospital (Al- Hilla teaching hospital and Imam Al- Sadeq teaching hospital). Purposive non- probability sample methods used to select the sample of the study to achieve the study objectives. The study sample consisted of (63) nurses divided as (30) nurses for interventional group, and (33) nurses for control group specific questionnaire prepared to collect the data by interview method. Most of participants 16(48.5%) and 19(63.3%) in both group (control and interventional) were between age group(24-26) years, 18(54.5%), 19(63.3%) were male, most of them were bachelor holder 22(66.7%) and 18(60.0%). Related to their marital status 17(51.5%) in the control group were married, while 17(56.7%)in the interventional group were single, when most of the demographical characteristics matched among the study group it mean the equivalence of the group. The pretest of both study group recorded unsatisfied level of knowledge related to communication with patients under artificial ventilation as (1.26 _+ 0.181), (1.30 _+ 0.197). During the posttest the control group shows the same poor level clearly, while the nurses who attend the educational program session recorded significant improvement in their two posttest as(1.76_+0.206) and (1.74_+ 0.216). This indicated the effectiveness of the content which presented in the educational program related to this issue. Significant improvement appear clearly among the interventional group member through the result of their pre and posttest, which explain the effectiveness of the educational program session content on the nurses knowledge. Training the nurses who work in intensive care unit about the communication with patient under mechanical ventilation.