The purpose of this study was to compare cognitive effects of two developmentally sequenced preschool curricula with outcomes of a traditional eclectic preschool curriculum. Specifically, pretest and posttest scores for children taught with the Brigance Diagnostic Inventory of Early Development and the Portage Guide to Early Education were compared with scores for children taught with the First School Experiences Program. The Cooperative Preschool Inventory was used for assessment. The study was conducted with children enrolled in Title I prekindergarten and Head Start classes in Cincinnati during 1981-82. Four prekindergarten teachers were assigned to each of the three comparison groups. Of approximately 380 children initially enrolled in the 24 participating classes, 320 remained for the posttest. Results indicated children in the Portage classes made less progress than children in either the Brigance or control classes. Since student record management problems were noted by all eight teachers in the experimental classes, it is possible that detailed assessment and record keeping demands interfered with instructional time. It was concluded that careful evaluation should accompany any major shift in curriculum so that effects can be identified early. (RH)