Two introductory passages, one regular passage, and one experimental advance organizer passage developed to facilitate initial learning were assigned to normal and retarded children. The subjects were 184 normal 8-year-olds (controls' mean IQ 118.00, organizers' 118.80) and 184 educable mentally retarded 15-year-olds (EMR controls' mean IQ 74.85, organizers' 76.06). No student had a reading level below 3.5 and the means for all groups exceeded 4.0 grade equivalents. All then studied a learning passage and responded to an achievement test which was readministered 2 weeks later. Normal organizer exceeded normal control performances on both immediate and delayed retention measures (p.05) but no significant differences between EMR organizer and control groups were found on either retention measure. It was speculated that the EMR-normal differences other than reading achievement and mental age were responsible for the differential utility of the advance organizer. Instructional practice in EMR classes, emphasizing concrete to abstract and specific to general subject matter sequencing, was suggested as antagonistic to advance organizer strategy and possibly responsible for the results. (Author/JD)