Background: umbilical cord blood is a rich source of stem cells, making it a valuable tissue resource in the clinical field of stem cell therapy and transplantation. Aim: evaluate effect of guideline on maternity nurses' knowledge about process of cord blood collection. Research question: what is effect of guideline on maternity nurses' knowledge regarding cord blood collection process. Research Design: Descriptive research design was utilized to fulfill the aim of this study material  and methods: setting This study was conducted at Minia university hospital & General Minia hospital.sample:convenient sample included 78 nurses. Tool: in form of structured self-administrative questionnaire developed by the researcher which include: socio-demographic characteristics, knowledge about cord blood banking, diseases that can be treated with umbilical cord blood, recommended procedures during umbilical cord blood collection and barriers in applying cord blood banking. Results: The main finding of the study were majority of sample have inadequate knowledge . Conclusion: health education was effective in increasing knowledge about umbilical cord blood banking .recommendation: these finding indicate need to Adequate planned in-services related to cord blood collection and banking must established to develop nurses knowledge, attitude and practice