In this article, the promoting effects of Cr, Mn, Fe, Co, and Ni on sulfated zirconia (SZ) catalysts for n-butane isomerization were studied and compared. The reactions were carried out at temperatures between 313 and 473 K with a WHSV of 0.5 g n-butane/g catalyst/h (i.e, feed stream of 4.3% n-butane in helium). Our results indicate that under these reaction conditions Fe is the most active promoter. The activities of Fe-, Co-, and Ni-, promoted catalysts increased with increasing temperature up to 473 K, and at temperatures where these catalysts were less active, their activity was decreased if hydrogen was used instead of helium in the feed stream. The Cr- and Mn-promoted catalysts, however, were not affected by the presence of hydrogen, and they reached a maximum activity between 333 and 473 K.