Congenital tuberculosis refers to tuberculosis caused by infection of the fetus before or during delivery. The routes of transmission can be divided into: 1) maternal hematogenous tuberculosis, where Mycobacterium tuberculosis enters the fetal liver through the umbilical vein and causes hepatic primary syndrome, or systemic disseminated tuberculosis through the umbilical vein and into the lungs through the venous catheter; 2) maternal endometrial or placental tuberculosis, where the caseous lesions break directly into the amniotic fluid and form tuberculous amnionitis, and the fetus inhales the amniotic fluid to cause disease; 3) maternal reproductive tract tuberculosis. During labor, tuberculosis bacteria from the birth canal enter the fetus’ respiratory or digestive tract through extrusion leading to tuberculosis infection and morbidity. The criteria for the diagnosis of congenital tuberculosis established by Cantwell et al. in 1994 were: 1) the presence of tuberculosis lesions within the first week of life; 2) primary syndrome of the liver or caseous granuloma; 3) the presence of Mycobacterium tuberculosis infection in the placenta or maternal genitalia; and 4) the exclusion of the possibility of postnatal infection. Two of the three children in this study had mothers diagnosed with hematogenous disseminated tuberculosis during pregnancy and postpartum, and one died suddenly after delivery. All the children were isolated from their mothers after birth, and there were no other tuberculosis patients in their families, so the possibility of acquired contact infection was excluded. After admission, all three children were discharged from the hospital with anti-tuberculosis treatment and gradually improved. As of September 2014, the three children had recovered significantly and were still being followed up. Although the above criteria are now widely used, some issues should be noted in the diagnostic process: 1. The time of onset of congenital tuberculosis is not invariable, as it has been reported in the literature that the onset can occur between 1 and 84 days. Because of the different immune status of each child, some children may have a slower onset of disease. 2. In the diagnosis of congenital tuberculosis, it should be noted that congenital tuberculosis is not diagnosed in younger children with tuberculosis and in mothers with tuberculosis. Similar cases can often be encountered in clinical practice. If the child’s mother has open tuberculosis, theoretically, the child’s tuberculosis is mostly transmitted from the mother’s respiratory tract, which does not meet the diagnostic criteria for congenital tuberculosis. 3. Disseminated BCG disease should be excluded. Since BCG vaccination in China is currently completed within 24 hours of birth, there is a partial overlap between the onset of disseminated BCG disease and congenital tuberculosis. Disseminated BCG disease has a clear history of vaccination, mostly local manifestations at the vaccination site, and a prominent tendency of lymph node involvement in the systemic manifestations. In this paper, all three children were vaccinated with BCG after birth as planned, but no significant abnormalities were seen at the vaccination site or in the ipsilateral axillary lymph nodes.4. Non-tuberculous mycobacterial infection (NTM) should also be ruled out in the diagnostic process. The diagnosis of NTM is still based on bacteriological grounds, and whether the infection is congenital or not can be determined by referring to the diagnostic criteria of congenital tuberculosis, the key is to distinguish whether the source of infection is maternal or not. Our experience in the diagnosis and treatment of three children with congenital tuberculosis is: 1. Clinically, the possibility of this disease should be thought of in children with clinical manifestations of fever, cough, shortness of breath, poor appetite, and hepatosplenomegaly within 2 months after birth, and when treatment with powerful antibiotics is ineffective, especially when the mother is a tuberculosis patient; 2. The immune system is not well developed in younger children, and PPD and T-SPOT tests in Therefore, negative PPD and T-SPOT cannot exclude the diagnosis of tuberculosis; 3. Clinically, children suspected of this disease should be searched for the etiological basis of tuberculosis infection as far as possible, such as finding tuberculosis bacilli in gastric fluid and sputum, or finding tuberculosis bacilli in tissue biopsy can confirm the diagnosis; 4. Early diagnosis of tuberculosis and timely treatment can improve the prognosis.