The term leishmaniasis comprises a group of diseases caused by different species of a protozoon called Leishmania. Leishmaniasis is found worldwide, and is considered to be endemic in 88 countries. There are three main clinical forms of leishmaniasis: visceral leishmaniasis, cutaneous leishmaniasis and mucocutaneous leishmaniasis. Exclusive involvement of the mucosa is very rare. We present a series of three cases of mucosal leishmaniasis located in the oral cavity. The fact that all three cases were recorded in Spain (an area where L. infantum is endemic), suggests that the latter was the causal agent. The only manifestation of leishmaniasis disease in the described cases was the appearance of an oral lesion. Treatment was provided in the form of meglumine antimoniate in two patients, with a favorable response. One of the patients left the hospital after diagnosis, without receiving treatment, and the subsequent course is not known. A review is made of the literature on the subject.