Objetive: Knowing the level of emotional overload which the main informal caregiver of a mentally ill person has to undergo when admitted to a subacute unit, and valuing the existence of mood disorders (anxiety or depression) in the caregiver himself/herself, along with the impact for the caregiver of the patient admitted in a subacute unit. Method: A descriptive and transversal study carried out from a sample of 32 main caregivers of patients in the Unite of the Subacute in the Psyquiatric Hospital of Zaldibar, during 2010, being the measure instruments for that purpose the Zarit Scales for Caregiver Burden and the Goldberg Anxiety and Depression Scale (GADS). Results: The level of overload presented by a 53% of these caregivers is intense, coupled by a predominantly anxious mood with an average of 5.34 on the Goldberg Anxiety and Depression Scale (GADS). After admission, 69% of these caregivers reduce the overlead, and 59.5% improve in both anxiety and depression. Conclusions: The task of caring falls primarily on parents who expressed particularly fear for the future of their sons and daughters, and feel that they depend heavely on them wich generate a lot of overload.