OBJECTIVES: Chiari I malformation has been a well-recognized clinical entity; however, its occurrence among infants and toddlers is unusual. Their clinical presentations may be different from other age groups due to their lack of effective verbal communication. The authors analyze their personal series of patients focusing on symptomatology and MRI characteristics. Treatment methods, results, and outcome are analyzed in order to identify appropriate surgical management among infants and toddlers with Chiari I malformation. METHODS: The authors retrospectively reviewed 16 patients who were diagnosed and surgically treated between 2007 and 2014 during the first 3 years of life with minimum follow-up of 3 years. We focused on the presenting symptoms, magnetic resonance imaging findings, and surgical techniques used for posterior fossa decompression (PFD) and their postoperative outcome. RESULTS: Twelve patients (75%) presented with signs of headaches such as irritability, inconsolable crying, head grabbing, and/or arching back. Ten patients (62.5%) presented with oropharyngeal and/or respiratory symptoms such as emesis, choking, gagging, snoring, sleep apnea, breathing pause, and/or vocal cord palsy. Only one patient had segmental cervical hydromyelia. At the first surgery, ten patients had PFD with dural scoring (Type 1 procedure), while six others had PFD with duraplasty (Type 2 procedure) with thermal reduction of the cerebellar tonsils in four. Following the first operation, all initially had varying degrees of symptomatic improvement; however, seven patients subsequently had symptomatic recurrence. Persistent crowding at the PFD site on the postoperative imaging indicated greater risk of recurrences in both Type 1 procedure and Type 2 procedure groups. Of seven patients who needed a second operation, fivewere after Type 1 procedure and the two were after Type 2 procedure. The difference of recurrence rates between these two groups is not significant. CSF-related complications occurred in 4 out of 11 patients who had Type 2 procedure (one after primary decompression and three after the second decompression for recurrence). CONCLUSION: Young patients lacking effective verbal communication often present their Chiari I malformation differently from olderage groups. Behavioral changes indicative of headaches/irritability and oropharyngeal/respiratory symptoms are the primary presenting symptoms. The recurrence rate tends to be higher among the patients after Type 1 procedure (particularly those younger than 18 months) than after Type 2 procedure. We observed that duraplasty at primary or at redo PFD provides for better decompression and long-term outcome. However, one should keep it in mind that there is risk of CSF-related complications following duraplasty, particularly higher tendency after redo PFD.