Melatonin is widely used for sleep disorders in patients with a range of developmental disorders and neurodisabilities, who also frequently have epilepsy. The aim of our review was to examine published data to assess the evidence for melatonin affecting seizure control. The literature search revealed 26 papers apparently reporting an association between melatonin and epilepsy or seizures but seven of these did not provide relevant information. Of the three double-blind, randomised, controlled trials, two showed no overall worsening or improvement in seizures, and one recent trial reported a statistically significant reduction in seizures. The open studies reported conflicting results. The few studies on the effect of seizures on melatonin levels have reported that baseline melatonin levels may be low in patients with uncontrolled epilepsy and that levels increase markedly following seizures. The striking finding of this review is the paucity of relevant data from the remarkably small number of studies. These results allow no firm conclusions to be drawn, although it would seem reasonable to observe that there was no marked overall effect on seizures, neither improvement nor worsening. There is a need for large, well designed, randomised, double-blind, placebo-controlled trials to establish the role of melatonin in either predisposing to or decreasing the likelihood of seizures.