Leather is a natural material with many applications: automotive, domestic upholstery, buildings, aviation, maritime, personal safety, etc. For each of these sectors, fire behavior is a field of particular interest. Unfortunately, there are many testing methods and different flammability standards depending on material application and end use. Therefore, there are different ways of approaching the whole flammability issue. In this work, different approaches for analyzing the fire resistance of leather are examined: (i) influence of the type of tannage, (ii) influence of the type of leather, (iii) influence of the type of retannage, (iv) influence of the type of fatliquor, and (v) influence of the use of flame retardants. The results indicate that leather presents natural fire resistance. However, the type of leather, type of tannage, retannage and fatliquor effect the flammability behavior of leather. In addition, the use of flame retardants slightly improves the smouldering properties of leather.