Serious sleep problems are common in children with an intellectual deficit (ID), and are often the source of much distress for both the child and caregivers. As yet, no satisfactory long-term treatment exists for intransigent sleep difficulties in children with an ID. Valerian, Valeriana spp., has been used for thousands of years to induce relaxation and sleep. Scientific investigation of valerian's sleep promoting ability in humans, whilst limited, has yielded promising findings. This initial study aimed to explore valerian's potential for assisting in the treatment of sleep problems in children with an ID. Five children with varying intellectual deficits and different primary sleep problems underwent eight continuous weeks of monitoring via sleep diaries, adhering to a double blind, placebo controlled and randomised design. Compared to baseline and placebo, valerian treatment led to significant reductions in sleep latencies and nocturnal time awake, lengthened total sleep time and improved sleep quality. The treatment was apparently most effective in children with deficits that involved hyperactivity. Although the findings are preliminary and in need of replication, there is evidence to suggest that valerian may be useful in the safe and effective long-term treatment of intransigent sleep difficulties in children with ID's, and therefore warrants further investigation.