Infectious diseases remain a significant concern for children under five, often leading to substantial morbidity and, in some cases, mortality. This review provides an overview of prevalent infectious diseases affecting this vulnerable age group, including Measles, Chickenpox, Common cold, Pertussis, Conjunctivitis, Eczema, Gastroenteritis, Influenza, Sore throat, Fever in children, Malaria, Meningococcal disease, and Urinary tract infection. Each condition is discussed in terms of its etiology, clinical presentation, diagnosis, treatment, and preventive strategies. Understanding the unique aspects of these diseases in young children is critical for effective management and prevention. Vaccination, improved hygiene practices, and early medical intervention play pivotal roles in reducing the incidence and impact of these infections. This comprehensive review aims to equip healthcare providers, caregivers, and policymakers with the knowledge needed to protect and promote the health of children under five. Key words Chickenpox, Common cold, Conjunctivitis, Eczema, Gastroenteritis, Infectious diseases, Influenza, Malaria, Measles, Meningococcal disease, Pertussis, Sore throat, Urinary tract infection.