We report a randomized, double-blind, controlled, crossover trial investigating the response to oral melatonin using two dose regimens in patients with sleep disorders associated with tuberous sclerosis complex. Eight outpatients with tuberous sclerosis complex and sleep disorder received either 5 or 10 mg of melatonin. Sleep latency, total sleep time, number of awakenings, and seizure frequency were recorded in sleep and seizure diaries. No evidence of a dose effect between 5 and 10 mg was seen with respect to any outcome measure. (The 5 mg results are given first: sleep latency, 86 and 76 minutes; total sleep time, 8 hours, 57 minutes and 9 hours, 4 minutes; and sleep fragmentation, 0.8 and 1.0). This study might have missed a small beneficial effect of 10 mg melatonin. We propose that an initial trial of 5 mg melatonin is worth considering in patients with tuberous sclerosis complex and sleep disorder.