Performance on a visual search task was contrasted for hyperactive boys and non hyperactive reading-disabled and presumably attention-disordered boys participating in a double blind, crossover study (methylphenidate vs. placebo). Mean dosage levels, individually titrated by the team psychiatrist, were highest for the reading-disabled group, lowest for those with suspected attention disorders. All three groups were seen by teachers and parents as significantly improved while on medication, and all groups dramatically reduced extraneous responses and attention lapses on the laboratory task. On a composite measure of performance and behavior, the non hyperactive subjects improved significantly more than the hyperactive subjects. Although given rather high average dosage levels (about 37.5 mg/ day or 1.25 mg/kg-day), the subjects did not deteriorate in search behavior, which entails short term memory. It is argued that the cerebral stimulants may be as beneficial for non hyperactive reading-disabled and attention-disordered children as for hyperactive patients, for the former have just as great difficulty sustaining attention as the latter.