Holding a letter in his hand, Juan Bautista Muguiro sits beside his desk, on which an inkwell is visible. This representation exalts his stature as a banker taking care of his business. An inscription mentions that the painting was made by Goya in May, 1827, in Bordeaux, when he was eighty-one. As the painter died in April 1828, this may well be his last known work.

There are some differences with his earlier works. The sure brushstrokes of his youth had lasted until his first years of old age; here, the sureness is broken, it trembles or becomes impalpable as a result of his advanced age and illness. Nevertheless, his technique is very elaborate, almost miniaturist, in the face and hands. The mixture of colors in the short and juicy brushstrokes reveal Goya's march toward modernity, even in his final painting.

Muguiro's liberal condition is present in the canvas with all the intensity of a real physical presence, and Goya reveals the tranquility, firm spirit and idealism of this character exiled for his political ideas.