This paper contains information about the conservation and restoration treatments applied to the work titled San Francisco at Prayer, by the Spanish artist Francisco de Zurbarán. The painting belongs to the Spanish Paintings Collection of the National Museum of Fine Arts in Santiago, Chile. It was found at an advanced deterioration stage, showing marks of horizontal foldings and embrittled edges. Prevoius interventions were evident: an old remounting with a new canvass had collapsed and considerable repainted areas were observed. Its critical condition prevented exhibition to the public, since the general image was exceedingly altered. An intervention was needed to repair the deterioration and return the painting to its original status as a work of art.