The average age of European population is growing year by year and the social impact of this trend will affect the future economy of developed countries. Since elderly people suffer from many chronic diseases that limit their capabilities; home assistance is one of the main emerging needs. One common aspect of advanced age is susceptibility to hypothermia due to several age-related physiological factors such as lower metabolism, thinner skin, malnutrition, and delayed perception of hot/cold. Hypothermia can lead to mortality during the night in elderly affected by diseases or disabilities. In this paper we present a pajama that aims to monitor elderly people while sleeping. Such a system, developed in the scope of EU funded project MOBISERV, is able to monitor a 1 lead ECG signal, upper body movements and skin temperature from 2 different sites through a distributed Body Sensor network, and communicate to a main data logger through ANT wireless protocol. The ultimate goal of the system is to prevent the onset of hypothermia by unobtrusively monitoring physiological parameters of a subject and raising alarms if wrong patterns are detected.