Introduction: Malformations of the cerebellum have been well-known to coexist with abnormalities of the oculomotor system. Rhombencephalosynapsis (RES) is a rare malformation of the cerebellum of unknown etiology in which the vermis is hypoplastic and the two cerebellar hemispheres are fused. The type of oculomotor disorders associated with RES is not well documented in the literature. Here, two cases are presented. Case 1: A 15-year-old girl presented with large-angle infantile esotropia and inferior oblique overaction. Slow (3 to 4 cps) rhythmic anteroposterior oscillation movement of the head was observed while walking and left-sided postural tremor was present. Case 2: An 8-month-old baby girl presented with facial dysmorphism, right esotropia, anisometropia, motor delay and truncal ataxia. Cranial MRI demonstrated RES in both patients. Conclusion: The clinical findings in two children presenting with infantile esotropia and RES may suggest a role of the vermis in ocular alignment. Head nodding in a child with strabismus can be observed only when walking and its presence should prompt neuroimaging. Copyright © 2008 Informa Healthcare USA, Inc.