There is a growing suspicion that survivors of bacterial meningitis have deficits which may not become apparent until the children encounter the stress of school. Controlled studies are needed to evaluate such subtle sequelae. The first study concerns the intelligence test results of 31 influenzal meningitis survivors, each of whom was paired with a near age sibling. All patients were ill before the age of 3, during 1960–64. All were tested at age of 6 to 15 years. The mean IQ of the postmeningitic (PM) children was 85 while that for sibling controls (C) was 97 (p = 0.04). It was found that 6 of 21 (29%) of the PM subjects were 15 IQ points (1 S.D.) and 2 (10%) were more than 30 IQ points (2 S.D.) lower than C while no C had an IQ which was 15 points below that of his affected sibling. The second study compared psychological test performance of 25 post-bacterial meningitic children, considered to be free of sequelae, who were controlled in regular public school classes in the first 3 grades. Each was matched by age, sex, social class and classroom membership with a peer control. All subjects were administered a battery of psychological tests. The results indicated that with each of the following, the PM subjects had significantly lower mean scores than peer controls. On the Illinois Test of Psycholinguistic Abilities, the psycholinguistic ages differed at the 0.004 level. On the Frostig Developmental Test of Visual Perception, the perceptual quotient differed at the 0.08 level. On the Peabody Picture Vocabulary Test, the vocabulary quotient differed at the 0.03 level. It is concluded that these survivors of bacterial meningitis function intelligently at a significantly lower level than their sibling or peer controls.