The study aimed to determine if melatonin could reliably induce sleep in children undergoing sleep EEG without affecting the usefulness of the EEG itself. One hundred and sixty three children (112 males, 51 females; mean age 8 years, range 1 to 16 years) referred for sleep EEG were studied. The children were given 2 to 10 mg of melatonin, depending on age, just before EEG recording. Measurements included sleep-onset latency, adverse effects, and acceptability of the EEG. Usefulness and acceptability of melatonin-induced sleep EEG were compared with the standard technique of sleep EEG following sleep deprivation in 30 children (matched for sex and age). Sleep was obtained in 79% of the 163 children who received melatonin after an average of 33 minutes. Yield of epileptiform abnormalities demonstrated in the melatonin sleep EEG was similar to that reported in the literature for sleep-deprived EEGs. There was no significant adverse effect. When compared, a melatonin-induced sleep EEG was as useful as a sleep-deprived EEG. However, the children's behaviour on the day of the melatonin-induced sleep EEG recording was more acceptable to parents.