In Greece it is quite common for family members to provide informal unpaid care for another family member during hospitalization, alongside healthcare professionals. Understaffing and lack of nursing personnel, due to austerity measures implemented in Greece during the last eight years, force families to provide informal care during hospitalization. The aim of the research was to study the role of informal caregivers (IC) during a family's member hospitalization, factors affecting their presence and patient's needs that were met by them. This cross-sectional study was conducted in five medical wards of a tertiary general hospital in big city of Northern Greece, during 14 weeks using a questionnaire with demographics, clinical data, and type and frequency of interventions performed by ICs. Patient/nurse ratio was also recorded. On the total, 210 ICs participated (63.42% response rate). The vast majority of ICs were females, married, close relatives and in their late forties. More than half of them (58.1%, n=122) stayed by their patient bedside for more than 17 hours per day, as it was found that 13.8 patients were allocated to each nurse. Less than one quarter of ICs reported that their patient's status was not serious at all and according to them, one third of the patients were totally dependent and one fifth were totally self-sufficient and able to take care of themselves. Nineteen out of the twenty three interventions performed by caregivers were interventions of basic nursing care. The GHS administration officials are called to consider nursing understaffing in order to provide adequate and safe care. As new personnel is very difficult to be hired, family members could be trained, through structured programs, in basic nursing skills and interventions, so that they could participate in their family member's care and provide continuity of care at home.