Undergraduate nursing students considered from the most vulnerable group who are at risk for SARS-CoV-2 infection. To protect undergraduate nursing students' healthcare authorities should keep them away from stress and anxiety and improve their knowledge, attitude, and practice towards COVID-19. The study aimed to assess knowledge, attitude, and emotional problems regarding COVID-19 among undergraduate nursing students. Methods: Design: A descriptive, web-based-cross-sectional study was used. A convenient sample of all 280 undergraduate nursing students in the Faculty of Nursing Sohag University was included in the study from 20 June to 2 July 2020. Tools: A self-administered related questionnaire was designed using Google forms regarding the COVID-19 related KA, the link of the survey was sent to the respondents via Whatsapp groups and depression, anxiety, and Stress Scale (DASS). Results: The majority of the undergraduate nursing students were knowledgeable about COVID-19 which indicating a high level of knowledge and indicating optimistic attitudes. As regard emotional problems, the result presents that 70 % of the undergraduate nursing students suffered from a moderate level of stress, while only 11 % were normal. Regarding anxiety level, detected that 60 % of the undergraduate nursing students suffered from moderate anxiety, while 18 % of them were normal. Related to depression level, 35 % of undergraduate nursing students suffered from a moderate level of depression. Conclusion: more than two-thirds of undergraduates nursing students suffered from a moderate level of stress, less than two-thirds of them suffered from moderate anxiety, while around one-tenth of them were normal, and more than one third of them suffered from a moderate level of depression. Recommendations: the study suggested the need for additional research on predictive factors affecting people's stress in the era of COVID-19 outbreak and carried out intervention activities through various mediums to help undergraduates nursing students become more knowledgeable during the COVID-19 epidemic.