Information about the mechanism of action and pharmacology of lamotrigine is summarized. A brief review of the literature on the use of this drug in people with intellectual disability is followed by a suggested framework for evaluating antiepileptic drugs in this population. The role of lamotrigine is systematically examined against the suggested framework. This leads to the conclusion that lamotrigine is a very favourable drug for treating epilepsy in people with intellectual disability because it has a broad spectrum of action, is effective in treating subtle seizures, shows no loss of effect with time, is not usually sedative, does not produce difficult-to-manage adverse effects, appears to have no direct adverse behavioural effects and is available in a range of 'patient friendly' preparations. However, it is important to use the drug wisely. This implies starting with low doses of lamotrigine and escalating the dose slowly to avoid adverse effects, especially rash, and being aware of drug interactions which could cause difficulty, including the prolongation of half-life with valproate, the pharmacodynamic interaction when it is added to carbamazepine and the pharmacokinetic interactions of lamotrigine with a number of antiepileptic drugs.