To explore the causes of persistent hoarseness in infants.One hundred and seventeen infants with persistent hoarseness treated in the department of otorhinolaryngology in Children's Hospital of Fudan University between June 2008 and July 2010 were retrospectively analyzed (all patients received antibiotic therapy for 2 weeks and the symptoms were not relieved after that). The patients were divided into three groups according to the age at first visit: 22 newborns,6 months old in 60 cases,12 months old in 35 cases. All patients had video laryngoscope examinations. Some of them received CT scan, cardiac ultrasonography and pathological examination in additional. The diagnosis was established by clinical history and imaging modalities, and the causes were analyzed subsequently.Among the 117 patients, 45 cases were vocal hypertrophy and hyperplasia (37.81%), 39 cases were vocal cord paralyses (32.78%), 7 cases were laryngeal hemangiomas (5.89%), 4 cases were laryngeal webs and cyst (3.36%), 2 cases were vocal cord polyps (1.68%), 2 cases were glottic incompetence (1.68%), 1 case was laryngeal papillomas(0.84%), 1 case was vocal code granulomas (0.84%), 1 case was glottis restricted by neck lymphangioma (0.84%); 4 cases were undetermined and 13 cases were no abnormalities. The percentage of patients with congenital heart diseases (19 cases) in vocal cord paralysis was 48.72%. The proportion of vocal cord paralysis in younger group was higher than that in elder one, their percentage were 50.00%, 36.67% and 17.14% respectively (χ(2) = 7.18, P0.05).A variety of causes can lead to persistent hoarseness in infants. The majority of them are vocal hypertrophy and hyperplasia, followed by vocal cord paralyze. Vocal cord paralysis is more common in younger infants than in elder ones, and the main causes are post-cardiac surgery and congenital heart disease.