Background: Leishmaniases are neglected tropical diseases of public health concern in Algeria. The immunocompromised patients with HIV, autoimmune diseases, or chronic alcohol abuse are at a higher risk of leishmaniasis. Herein, we present the case of an immunocompetent diabetic patient infected by Leishmania major, leading to lifethreatening consequences. Case presentation: An Algerian diabetic patient developed a cutaneous lesion with large polymorphous inflamed granuloma and pyoderma gangrenosum in the left foot, following L. major infection. A delayed follow-up led to a treatment failure, resulting in the amputation. Conclusions: This report highlights the absence of timely treatment of Leishmania infection as a life-threatening point among high-risk diabetic patients. Clinicians should be aware of this parasitosis leading to severe complications in diabetic patients.