Congenital syphilis has been and continues to be a principal public health problem in developing countries. Despite the wide experience acquired, physicians still have problems in diagnostic evaluation. We report 88 cases of congenital syphilis at Central Hospital of Maputo (Mocambique), emphasizing the role of serological and roentgenographic examinations, the 2 commonest diagnostic tools. X-ray examination was particularly important to confirm the diagnosis of congenital syphilis in 76.2 percent of sero-positive children and to sustain the diagnosis in another subgroup of seronegative children (4.5 percent). Periostitis was a constant finding in all positive x-ray examinations and was associated with osteochondritis in 47.7 percent and with osteomyelitis in 18.2 percent of cases. Serologic test for syphilis was positive in 95.4 percent of the study population and was essential to make the diagnosis in 19.3 percent of cases with negative x-rays examination. So, laboratory and, in a complementary way, roentgenographic findings allow to confirm the diagnosis of congenital syphilis in 100 percent of cases. Serological test in the mother is a useful examination as well, with a high percentage of positivity (78.4 percent); however in accordance to the present study it fails to add any new case of congenital syphilis already detected by serological and roentgenographic examination in the child.