Tuberculosis (TB) is caused by Mycobacterium Tuberculosis. The disease primarily affects the lungs but can involve also other organs and systems. A diagnosis was difficulty conducted on a case of primary tuberculosis concerning a 22 year old male patient who complained about having a severe pain on the left maxillary accompanied by swelling in the left mandibular angle that appeared a month later with general symptoms (fever and weight loss). The intraoral examination revealed an ulceration that is located in the buccal and palatal mucosa facing mobile 26 and 27. The panoramic radiography didn't reveal any specific character. The presence of tuberculosis was confirmed by histology. The diagnosis and clinical presentation of the lesion is uncommon and emphasizes the importance of considering tuberculosis in the differential diagnosis of oral lesions that affects the mucosa and the gingiva.