Infantile meningitis is a clinical diagnosis. However, suspicion of its complications may warrant further investigations; and transfrontanelle ultrasound is a reliable and cheap way to evaluate the usefulness of ultrasonography in diagnosing the complications of infantile meningitis. This is a retrospective study of the transfrontanelle ultrasound findings in 40 infants presenting with clinical indicators of complicated acute bacterial meningitis. There were 20 boys and 20 girls aged 5-115 days (mean, 42.6+/-30.1 days). The complications of meningitis detectable on ultrasound were: hydrocephalus (21[52.5%]); cerebral abscess (2[5%]); subdural empyema (2 [5%]); and ventriculitis (3[7.5%]). Twelve babies (30%) had no abnormal findings. Hydrocephalus is the most common complication of meningitis in our setting. Transfontanelle ultrasound proved to be very reliable in the initial diagnosis and follow-up of complicated meningitis.