The aim of this study was to report the clinical and laboratory characteristics of bacterial pneumonia related to measles infection, and also to assess any correlation between severity and time of onset.Four hundred and twenty-four previously healthy young males (age 222.1 yrs) were hospitalized with typical symptoms and signs of measles. One hundred and twelve (26%) developed bacterial pneumonia on admission (n=41), during their hospital stay (n=20) or days after their discharge (n=51): groups A, B and C, respectively.Single lobar consolidation was the most common finding, accounting for 89% of cases. Pleural effusion was uncommon and associated in half of the cases with empyema. A microbiological diagnosis was made in 81 cases. Streptococcus pneumoniae (65 cases) and Klebsiella pneumoniae (9 cases) were the most commonly identified organisms. Patients from group C had significantly higher values of white blood cell count and erythrocyte sedimentation rate, and lower values of arterial oxygen tension (140.8610 9 . L -1 , 884 mm and 6.30.4 kPa (473 mmHg), respectively) than the other two groups. There were no deaths during the hospitalization period. The mean duration of hospital stay was 132.4 days and was longer in the presence of K. pneumoniae infection (191.6 days). Six patients from group C were admitted to the intensive care unit.In conclusion, these data suggest that bacterial pneumonia associated with measles is not unusual in hospitalized adults, and it seems to be more severe when it occurs days after the onset of rash.