Haematological side effects are rather exceptional with lamotrigine. We report the case of a 25-year-old woman with epilepsy who developed combined leucopenia and thrombocytopenia eight weeks after starting lamotrigine. Within weeks after lamotrigine was discontinued, all of the haematopoietic abnormalities had disappeared. To our knowledge, this is the first report of combined leucopenia and thrombocytopenia associated with lamotrigine treatment suggesting, in our patient, a causal reaction.