We report 11 infants with infantile spasms who had partial seizures that occurred concurrently with the infantile spasms. We studied this phenomenon with time-locked video electroencephalography. The partial seizures began before the infantile spasms and continued after one or more infantile spasms in seven patients. An infantile spasm occurred at the beginning of the partial seizure in five patients. (One patient had both seizure types simultaneously.) The clinical descriptions of these combinations of seizures were confusing, since they did not match known seizure types. The genesis of these seizures may involve an interaction between processes of focal cortical epileptogenesis (partial seizures) and brain-stem synchronization (infantile spasms).