Dissertation (MSc Paediatric Nursing)Background: Pneumonia is responsible for killing at least 1 million children under age of 5, every year: Over 70% of these deaths occur in developing countries. This study intended to determine the impact of pneumococcal conjugated vaccine, on the prevention of pneumonia among children from 6 months to 5 years in Zanzibar. Methods: Study design was a cross-sectional, which employed a quantitative research approach. The study utilized multiple sampling techniques with purposive sampling technique to select the regions and the districts. Additionally, a simple random sampling by lottery was used to select shehia and study participants. A total of 520 respondents were involved in the study, whereby caregivers were responsible on behalf of their children. The study utilized documentary review and questionnaires as the methods for gathering data. The questionnaires contained closed ended questions which were administered to all 520 caregivers. Both descriptive and inferential analysis was done, using SPSS version 20. Results: Majority of participants 48.8% were coming from the urban west, of whom 52.3% were males. Mean age 2.16 (SD= 0.733), whereby vaccinated children were 95.6% and non-vaccinated 4.4%. The prevalence of pneumonia was 32.3%. PCV uptake was 95.6%. Those children who were not vaccinated (AOR 21.696, 95% CI 6.525, 72.137) as compared to vaccinated children. Factors which was observed to contribute to these problem were incomplete dose on time (AOR 34.484, 95% CI 8.965, 13.484), age of children (AOR 0.431, 95% CI 0.243, 0.764), age of caregiver (AOR 4.407, 95% CI 1.581, 12.283) and malnourished children (AOR 1.581, 95% CI 1.069, 2.340). Conclusion: Vaccination with pneumococcal conjugated vaccine significantly, reduced the burden of pneumonia because majority whom were vaccinated and completed all 3 doses within 6 months of age, were free from diseases.