Background: Despite the fact that fever, changed into considered as a protective response for lots of decades and changed into even induced through doctors to fight certain infections, the using of antipyretic drugs has led to the common perception that fever is maladaptive and harmful. Parents have several misconceptions and beliefs about fever. Parents' fever phobia lead to inappropriate treatment of childhood fever. Parents' scores of the dangerous effects of fever have modified from past to present, even though their fundamental worries continue to be brain damage, febrile convulsions and death. This study aimed to develop nursing care guidelines to improve mothers' practical knowledge in caring for their feverish children. Research design: a quasi-experimental research design was conducted in inpatient and outpatient departments of Mansoura University Children's Hospital to achieve the steady aim. Subjects: a purposive sample of 100 mothers who were attending the previously mentioned two settings were selected. The results of this study revealed that, there has been a statistical improvement in mothers' knowledge pre implementation of care guideline, immediately after and follow up 40%, 100% & 100%, respectively, and mothers' practices 47%, 100% &99% respectively in caring for their feverish children. The study concluded that, there was a positive impact of care guideline on improvement of mothers' practical knowledge in caring for their feverish children. The study recommended availability of guidelines (a handbook) of fever and its management as a source to all mothers in the hospitals.