Background: Environmental health (EH) has various effects on man such as chemical, physical, biological, social, and psychological problems. Also, it is the theory and practice of assessing, correcting, controlling and preventing harm to human health today and in future generations. Nurses are in primary position in dealing with patients and public health. Nursing knowledge is key to advocacy and care in environmental health. Inclusion of an environmental focus in a public health simulation scenario provides nursing students with knowledge and understanding of environmental health and its impact on clients and communities. This study aims to assess the effect of an educational program on knowledge and practices about environmental health among 2 nd year nursing institute students, general department. Research design: A quasi experimental pre-posttest was used. Subjects: all nursing students who are enrolled in the 2nd year at Technical Health Institute, Zawet Ghazal area, general department and accepted to participate (n=180). Data collection: by two tools, 2 self-administered questionnaires were designed. Tool one was used to assess the students` knowledge regarding environmental health. Tool two ,the modified environmental health risk appraisal, was used to assess environmental health teaching points, which students taught clients during home visits after the EH educational intervention. An environmental intervention program was introduced to participants. The study was performed in three phases pretest, posttest and follow up. Results: the student nurses need to get more knowledge regarding environmental health aspects to improve their knowledge and health teaching practices. After the environmental intervention program the students' knowledge and health teaching practices were improved. Conclusion: significant positive changes in the level of knowledge of the participants after implementation of the environmental educational program. Recommendations: Implement comprehensive environmental educational program in the curriculum of technical health institute..