Procedure Participants will be recruited through several procedures. First, posters and brochures with information about the study will be available at the medical attention boxes, so that patients interested in participation could contact the research team by email or phone. In addition, one of the nurses of the medical center will contact by phone all the fibromyalgia patients registered in the medical center to ask them for permission to put them in contact with the study research team. Participants who agree to be contacted will received a phone call by a research assistant, who will provide them with further information about the study and - in order to corroborate that they indeed meet the inclusion criteria for fibromyalgia and mayor depression -ask them to respond to the Fibromyalgia Survey Questionnaire (FSQ; Wolfe et al., 2011; Carrillo de la Peña et al., 2015) and the Patients Health Questionnaire-9 (PHQ-9; Baader et al., 2008). Participants who meet inclusion criteria will be scheduled for a diagnoses interview according to Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV) criteria. The Mini-International Neuropsychiatric Interview (MINI; Ferrando, Bobes, & Gilbert, 1999; Sheehan & Lecrubier, 1999) will be applied in order to make the diagnoses. In addition, the Mini-Mental State Examination (Folstein, Folstein, & Mchugh, 1975, González-Hernández et al., 2009) will be administered. All participant will be asked for informed consent before participation. Participants who meet all the inclusion criteria after this interview will be randomized to the two arms. Randomization will be conducted by a research assistant (other than those who will perform the assessments, treatment and data analysis) using a computer program. As a compensation, patients will receive gift card (with a value of 10.000 Chilean pesos) after each outcome assessment interview.