The organ of San Baltazar Yatzachi el Alto is an excellent example of Oaxaca organ building in the 19th century. The case is decorated with typical neo-classical carvings: denticles on the cornice, serrated open carved work on the pipe shades and around the profile of the upper case, and lambrequins on the lower case. The date 1835 is inscribed on the right side of the case, which provides a baseline for similar undated organs. The keyboard includes 47 notes in the right hand, an unusual feature at the time. The organ is nearly complete, although unfortunately damaged by woodworm. The ceiling of the church is splendidly decorated with colorful geometric patterns.