ProQuad is a recently approved combination vaccine for simultaneous vaccination against measles, mumps, rubella and varicella in children aged 12 months to 12 years. It combines two well-established vaccines: Measles, Mumps, Rubella Virus Vaccine Live (M-M-R II) and Varicella Virus Vaccine Live (Varivax with higher varicella-zoster titer). Whereas vaccination against measles, mumps and rubella has almost 100% coverage, vaccination against varicella shows a significantly lower uptake of approximately 84%. Clinical studies on the immunogenicity and efficacy of ProQuad demonstrated seroconversion rates and a magnitude of antibody response similar to those observed after administration of its individual components, M-M-R II and Varivax vaccines. The incidence of local side effects (pain/tenderness/soreness, erythema, swelling, ecchymosis and rash) and systemic adverse effects (fever, irritability, rash, upper respiratory infection, viral exanthema and diarrhea) is similar to or lower than that observed in component vaccines. ProQuad is a highly immunogenic combination vaccine with a good safety profile. The use of ProQuad combination vaccine will simplify immunization delivery by providing protection against more diseases with fewer injections and less pain, improve timely vaccination coverage and reduce the health-care costs for additional health visits. The ProQuad combination vaccine facilitates implementation of varicella vaccination into routine childhood immunization schedules and will help to protect children against these four potentially serious diseases.