Genomic imprinting is a parent-of-origin epigenetic regulatory mechanism that regards a small subset of genes genome-wide and that exerts pivotal functions in the developing brain and in behavior. A growing corpus of data indicates that genomic imprinting significantly impact on sleep-wake cycles and behaviour. Genomic imprinting in endothermic animals is involved in specific functions that counteract hypothermia. Several imprinted genes that are expressed in brown adipocytes control the thermogenesis process along the day. To date we have investigated both direct (central) and indirect (i.e., due to thermoregulation) roles of imprinted genes on sleep. Here I will present published and unpublished results showing specific parent-of-origin effects in the control of REM/NREM sleep and in fine behavioural processes. The link between imprinting, thermoregulation and sleep provides a new point of view into the evolution of both epigenetic mechanisms and sleep physiology.