Background:Streptococcus pneumoniae(S. pneumoniae)is an important pathogen responsible for numerous infections in humans particularly children under 5 years causing unparalleled fatality.Aim:This study set out to determine the prevalence and circulating serotypes of Streptococcus pneumoniaein under 5 years old children attending Toro General Hospital, Bauchi State, Nigeria.Methods:The study was cross-sectional, and hospital based. A total of 114 nasopharyngeal swabs were collected from children < 5 years old.Streptococcus pneumoniae was isolated, biochemically identified, and molecularly confirmed using PCR via the gene marker CpsA. Latex agglutination was used to serotype the confirmed isolates.Results: a prevalence of 22.6% was established in this study for S. pneumoniae. The age group 0 – 11 months had the highest prevalence of 28.1% while 36 – 47 months had the least prevalence (11.8%). Males had relatively higher prevalence of 29.0% compared to females (20.0%). There was no significant association between the carriage of S. pneumoniae, age, and sex (p < /em>> 0.05). Though there was no significant association between vaccination status and prevalence of S. pneumoniae (p < /em> = 0.937), non-vaccinated group had lower prevalence of 22.4% as opposed to 23.1% in the vaccinated subjects. Six circulating serotypes [1 (23.1%), 6 (34.6%), 9 (3.8%), 11 (11.5%), 19 (3.8%), and 23 (3.8%)] were detected. Serotypes 1 and 6 were found in both vaccinated and non-vaccinated children but serotypes 9, 11, 19, and 23 were detected in vaccinated children only.Conclusion:PCV vaccine and non-vaccine S. pneumoniae serotypes were found to be prevalent and circulating among under 5 children in the current study.