To analyse the informal system of caring for people with neuro-degenerative disease: what it consists of and the characteristics of main carers, the type of care given, and the consequences for the main carer of assuming these functions. Descriptive cross-sectional study conducted by means of a home-filled questionnaire. Autonomous Community of Andalusia. 72 main carers of someone with neuro-degenerative disease, chosen from a sub-sample of 1000 homes in which at least one dependent person lives and receives care from a member of his/her family or social network with whom he/she resides. This sub-sample was based on a random sample of 3160 Andalusian homes stratified proportionately according to province and size of dwelling. In 86.1% of the 72 homes polled, health care was provided only by the informal system network. In over half the homes, care was provided by just one person, the main carer. The main carer was usually a woman (87.4%), with an average age of 54.52, house-wife and close family member of the sick person. In our study the beneficiaries of care had an average age of 77.63, a low level of autonomy in daily activities, and had had a neuro-degenerative disease for an average of 8.16 years. The main kinds of care provided in the home for people with neuro-degenerative disease were help in instrumental activities, care related to daily activities, observation/company and supervision of medicines. Main carers believed that undertaking this work had seriously affected their health (72.2%), the use they made of their time (84.7%), their social life (83.3%) and their economic position (44.4%). People with neuro-degenerative disease make considerable demands on health care provision, which is mainly covered at home by the immediate family network. In most cases this network consists of just one person, the main carer, on whom falls the entire burden of care. The assumption of this role directly affects the health of a large number of carers, as well as other areas of their lives, in particular the possibility of conducting a social life and using their time for themselves or for activities other than caring.