Background: Postpartum depression is a serious public health problem because of its demonstrated adverse consequences on the development of maternal confidence and the cognitive, emotional and social development of their infant. Aim of the study: was to, find out the predicting variables of postpartum depression, determine its help seeking barriers and evaluate the impact of an educational program on upgrading nurses' knowledge pertaining to the assessment and prevention of postnatal depression. Subjects & methods: Research design: A case control design and an intervention design. Setting at two Maternal and Child Health Centers. at Zagazig University Hospitals. Subjects: 400 puerperal women were recruited randomly as a first sample and the second sample included 20 maternity nurses working in antenatal, natal and postnatal units .Tools of data collections: an interview questionnaire, Edinburgh Postnatal Depression Scale, Postpartum Depression Screening Scale, Short Explanatory Model Interview, help seeking barriers questionnaire and nurses ' knowledge questionnaire. Results: post natal depression was associated with low educational attainment (11.0%), financial difficulties (17.5%), unwanted pregnancy (30.5%), and unsuccessful breast feeding (27.5%) .Factors predicting of postpartum depression include, feeling of depression and anxiety during pregnancy (78.0% &94.0%), lack of social support (55.0%), low self- esteem (77.0%), marriage problems (69.5%). Almost two fifth of cases (57.5 %) did not seek help for their depression. Statistically significant improvements were revealed at both the post and follow-up phases in all areas of tested knowledge .Conclusion: The implementation of an educational program was associated with high significant improvement in maternity nurse's knowledge in both the post and follow-up phases. Recommendation: nurses need to keep abreast of current knowledge and researches to be knowledgeable about postpartum depression and to ensure thorough assessments. They should also know about resources in their communities for treating postpartum depression to promote appropriate referrals