Background: According to a survey carried out by the National Institute of Statistics and Geography, the LGBTI+ community constitutes 5.1% of the population over 15 years of age. Within the medical services that these patients use, 52.2% are treated in public institutions where they are attended by general practitioners. Mexico doesn´t have doctors specialized in patients from the Trans community in public health institutions, so knowledge in the management of first contact doctors is essential to provide quality care to this population. Objective: To determine the sociodemographic factors associated with the degree of doctors knowledge about the transsexual and transgender patient Methods: An observational, analytical, cross-sectional and prospective study was carried out applying a Questionnaire of Knowledge about the Care of the Transgender Patient (a. Cronbach 0.77) that has a maximum of 42 points. General practitioner, medical interns and family physician from Veracruz, Mexico was included. The variables age, gender, sexual orientation, training on the topic, religion, workplace, university graduation time, previous care of LGBT+ patients and having friends from the LGBT+ community were studied. Results: 116 doctors were included, 54.3% were men, 87.9% were cisgender, 69.0% heterosexual, aged 30.4(±11.2) years. The results of the knowledge test show a score of 16.6 (±5.6) correct answers, with a maximum of 29 and a minimum of 4; 20.7% with a score higher than 21, showing differences (p0.05). Conclusions: The level of knowledge of primary care physicians is very low, so it is necessary to provide formal training in this area, since despite having factors associated with "higher" knowledge, this level is insufficient for according to the observed scores.