We examined short duration perception (400 ms), long duration estimation (30 and 60 min), and spatiotemporal estimation in long-term survivors of childhood cerebellar tumors with a mean time since diagnosis of 14.2 years. Groups of individuals with tumors treated with surgery only (astrocytoma, N = 20) were compared to those with tumors treated with surgery, focal radiation, and craniospinal radiation (medulloblastoma, N = 20), and to age- matched controls (N = 40). Childhood lesions of the cerebellum produced enduring deficits in short-duration perception, but spared the ability to functionally estimate long durations, regardless of the pathology or treatment of the tumor. Evidence did not support any functional recovery over time of the cerebellar system that underlies short-duration perception. Younger age at treatment was not a protective factor. Although no group differences were present in the functional measures of long-duration estimation, tumor-related prospective memory deficits interfered with the ability to produce long-duration prospective estimates. The utilization of sensory and somatomotor information to refine real-world spatiotemporal estimates was compromised in the medulloblastoma group only. (JINS, 2000, 6, 682–692.)