Cardiac resynchronization therapy (CRT) is a therapeutic option of increasing importance for chronic heart failure (CHF) and criteria for implantation now concern a large amount of patient populations. As a consequence, subjects with ongoing CRT (or immediately after CRT implantation) are more often referred to Cardiac Rehabilitation (CR) programmes, and it has been recently estimated that about one third of CHF patients attending CR in Italy currently have this kind of device. The presence of CRT represents a modulating factor for exercise prescription and monitoring, since CRT patients may be considered per se as a target group for CR. Exercise therapy (ET) increases benefits from CRT on functional capacity, and recent evidence suggests an adjuvant role of ET in improving cardiovascular prognosis also. Both aerobic endurance and resistance training activities may involve CHF patients with CRT, while the potential role of aerobic interval training needs more studies and evidence. Prescription of an ET program should be associated with information regarding device programming and possible limiting factors associated with pacing therapy, tailoring of the basic principles of ET (in terms of type of exercise, intensity and program duration) in this patient group is mandatory.