Streptococcus pneumoniae, or pneumococcus, is a leading cause of morbidity and mortality in children worldwide. Pneumococcal conjugate vaccines (PCV) reduce carriage in the nasopharynx, preventing disease. We conducted a pneumococcal carriage study to estimate the prevalence of pneumococcal colonization, identify risk factors for colonization, and describe antimicrobial susceptibility patterns among pneumococci colonizing young children in Port-au-Prince, Haiti, before introduction of 13-valent PCV (PCV13).