Background: Outbreak is an infection control challenge in health care setting especially when it occurs in a special setting as psychiatric hospitals. Objectives: Investigate and control an outbreak of varicella among patients and healthcare workers (HCWs) in a psychiatric hospital of Saudi Arabia. Methods: A multidisciplinary team of different specialties assigned to assess the situation, confirm the diagnosis, identify the causes and put an action plan to deal with such a situation. Results: The team investigated the varicella outbreak as per the Ministry of Health's (MOH) outbreak guidelines. Multiple risk factors contributed to this outbreak as the location of the outbreak in a psychiatric hospital, breaches in the hospital infection control program. Conclusion: Investigation of this outbreak was conducted as per MOH and CDC definitions and guidelines. Outbreak control plan was instituted and successfully implemented including enforcement of infection control program, the establishment of an employee health program, basic infection control orientation programs.