A modular medical device employs a defibrillator/monitor (20) and one or more pouch modules (60). The defibrillator/monitor (20) includes a defibrillator and/or an electrocardiogram (“ECG”) monitor (e.g., a defibrillator module and a ECG monitor module). Each pouch module (60) is permanently or detachably adjoined to the defibrillator/monitor (20) and is structurally configured to store one or more accessory items (40, 50) in support of an operation of the defibrillator/monitor (20) (e.g., ECG cable(s), electrode(s), transducer(s), pad(s), data storage device(s), paper, communication device(s), first aid product(s)/fluid(s) and medical supply(ies)/tool(s)). Alternatively, a cradle module (70) having a frame may be employed by the modular medical device to adjoin the pouch module(s) (60) to the defibrillator/monitor (20) and may partially, if not entirely, encircle the defibrillator/monitor (20). The pouch module(s) (60) and/or the cradle module (70) may include storage covers to secure the stored accessory item(s) (40, 50) within the pouch module(s) (60).