To determine whether consensus existed among teachers about the complexity of common classroom materials, a survey was administered to 66 pre-service and in-service kindergarten and prekindergarten teachers. Participants were asked to rate 14 common classroom materials as simple, complex, or super-complex. Simple materials have one obvious part, have no subparts enabling multiple combinations, and support children's activity for short periods of time only. Complex materials have subparts or two essentially different items together. Super-complex materials have three or more essentially different elements combined, or they include a markedly different object added to an already complex material. Items rated were: (1) a ball; (2) sand without props; (3) a set of Legos; (4) an obstacle course made of tires, boards, and boxes; (5) a block area with small props and large crates; (6) a single book; (7) an outdoor commercial wooden climbing structure; (8) blocks with no props; (9) crayons; (10) playdough without props; (11) a well-equipped dramatic play area; (12) pegs and pegboard; (13) wet sand for digging, pouring, and making impressions with tools; and (14) a guinea pig, gerbil, or rabbit. Teachers were in substantial agreement, viewing as simple 1, 2, and 6; as complex 3, 8, and 12; as super-complex 4, 5, 11, and 13. Discrepancies in teachers' ratings were found for items 7, 9, 10, and 14. The extent of consensus is taken as support for the ideas of Kritchevsky, Prescott, and Walling (1969). (RH)