A retrospective study of infectious diseases has been performed in 194 small-for-date full-term babies, finding septicaemia in 7.2% of cases, urinary tract infection in 5.2%, meningoencephalitis in 1% and enterocolitis in 3%. Most frequent infections agents were: 1) in septicaemia, Klebsiella pneumoniae (28.5%), E. coli and staphylococcus coagulase negative (21.4% for each); 2) in urinary tract infections, Klebsiella pneumoniae and E. coli (40% for each); 3) in meningoencephalitis, Klebsiella pneumoniae and E. coli (50% for each), and 4) in enterocolitis, E. coli (50%) and rotavirus (33%). Overall mortality rate was 4.1%, being 14.3% in the group with septicaemia (14 babies). Incidence of septicaemia is significatively related to assisted ventilation, catheterization of blood vessels, anemia and intravascular disseminated coagulation.