Fifth-day fits are a rare type of seizures in the infant. Tonic-clonic seizures have not been reported as a manifestation of this condition. This article presents a report of one patient and the value of video-electroencephalogram recording in assessing seizures, background electroencephalogram, and treatment. We describe a full-term female infant with fifth-day fits presenting with generalized tonic-clonic seizures associated with generalized electrical discharges, with normal background electroencephalogram activity between seizures. The fits rapidly responded to phenobarbital.