Behaviour problems are common in children with epilepsy and it is not known when these problems begin. Some suggest that behaviour problems are caused by a neurological condition that also causes the seizures. Behaviour problems were investigated in 42 youths (23 girls and 19 boys) over a 4-month period beginning at the time of the initial seizure. Subjects were aged 4-15 years (mean, M = 8.4). Approximately 57% had partial seizure(s) and 43% had generalized seizure(s). The large majority (71%) were diagnosed with epilepsy. As a part of a larger study, parents rated their children's behaviour on the Child Behaviour Checklist immediately prior to the first seizure (time 1), and at 4 months after the first seizure (time 2). Seizure severity was rated as follows: high = 20%, moderate = 39%, and low = 41%. At time 1, 24% already had behaviour problems. Behaviour problems significantly decreased from time 1 to time 2 (P < 0.001) for the whole group. Within the epilepsy group (n = 40), differences were found in behaviour problems based on seizure severity from time 1 to time 2 as follows: low, time 1: M = 55, time 2: M = 45; moderate, time 1: M = 55, time 2: M = 51; and high, time 1: M = 61, time 2: M = 55. Results indicate that children should be assessed for behaviour problems at the time of the first seizure.