Aims: To describe a case of neonatal lupus and complete atrioventricular block in Mexico. Presentation of case: A 38 years old pregnant patient at  28 + 6 weeks of gestational age, diagnosed with systemic lupus erythematosus six years ago, under treatment with hydroxychloroquine and prednisone, this was suspended eight months prior to pregnancy; and resumed at week 20 of gestational age. The ultrasound scan showed alive fetus, female, polyhydramnios and bradycardia. Fetal echocardiography confirmed complete atrioventricular block, without organic and structural alterations at the cardiac level. Furthermore, the immunological panel reports, positive anti-Ro antibodies. At week 33 of gestational age, the patient was admitted to the obstetric emergency room, through colic type pain and 4 cm dilation of the cervix. Alive newborn got vaginally with a weight of 1,990 g, a height of 43 cm and APGAR 8-9. Echocardiography confirmed congenital complete third degree atrioventricular block; without structural abnormalities. Discussion: Patients with systemic lupus erythematosus, are more likely to have complications during pregnancy. Neonatal lupus is a rare disorder with an incidence of 1:10,000 - 1:20,000 newborns. This is caused by the transplacental passage of maternal autoantibodies anti-SSA / Ro and/or anti-SSB / La. Besides Atrioventricular block is a complication of neonatal lupus, occurring in approximately 2% of newborns of mothers who have SSA or SSB antibodies. The most interesting finding is that 20% fetal mortality has been for this cause. Conclusion: The described case is important for its rarity. Besides, the imaging findings and immunological panel emphasized the relevance about complete and adequate evaluation of the fetus, in the context of a mother with systemic lupus erythematosus.