The progresses of neuroimaging have allowed an earlier detection of hypothalamic hamartoma in children presenting with gelastic or dacrystic seizures. Associated symptoms can include other types of seizures, precocious puberty, and behavioral or cognitive deterioration. Combination of all these features is not constant and, when present, their evolution may be variable. When epilepsy proves intractable, surgery may be a solution but is not without risks. Therefore, it can only be justified on the basis of a considerable degree of certainty on the progressive character of the disorder, both in terms of epilepsy and global development. Even though epilepsy is a major and usually the most important problem, it is not always possible to predict its course and to be able to evaluate its potential effects on development. Available data suggests that deterioration is partly related to the epileptogenic activity. We reviewed data from 16 personal cases and discussed the possible evolutions of the epilepsy syndrome on the basis of 6 illustrative cases and a review of the literature. We point out that seizures may start early in life and evolve either towards a catastrophic encephalopathy or may be transiently severe and will progressively settle down. Intermediate situations also exist as well as cases presenting with a mild epilepsy. In almost all cases cognitive difficulties are present and may be associated with behavioral disturbances. They are of variable severity, usually in relation to the severity of the epilepsy and the evolution of the EEG abnormalities. Some of our cases also illustrate that, in young children whose seizures are limited to "a sensation of a pleasant feeling", "a pressure to laugh" or "smiling", early detection of the hamartoma may still be difficult and the epilepsy pattern may be misdiagnosed as an epilepsy temporal or frontal origin. Detailed analysis of the electro-clinical evolution of representative cases highlights the variable expression of the epilepsy syndrome and renders difficult any dogmatic position on early surgery. However, recent data suggests that a surgical solution must be sought early. Prospective studies are needed to evaluate, not only outcome in terms of control the seizures without unacceptable side effects but also on the evolution of the cognitive and behavioral profile of children with HH and epilepsy are needed.