Macrocephaly, increased intracranial pressure, and hydrocephalus are common related conditions that lead to cross-sectional imaging of the infant and young child. Imaging plays a central role in establishing the diagnosis and guiding disposition and treatment of these patients. In this review, a general overview is provided, and the more common causes of hydrocephalus are presented, including posthemorrhage, postinfection, developmental malformations, and masses. Imaging guidelines are also outlined for initial evaluation and follow-up, along with a discussion of the imaging features of shunt malfunction.