Moncayo's artwork is realistic and it is distinguished by the harmony of elements and colors, and by the perfection of its minuscule details.
In minor scale, the artist also painted other themes such as horses, still lifes, and colonial scenes.
His paintings capture customs, flora, fauna, and scenery that have been changing through time and modernity.
In addition to their beauty and artistic value, O. Moncayo's paintings constitute a legacy to the Ecuadorian's culture and history.
His paintings mainly belong to museums, galleries, and private collections in Ecuador, Venezuela, and the United States.