A study investigated the contributions of phonemic knowledge, prior knowledge, and listening comprehension to the reading comprehension of elementary age children. Three theoretical perspectives were followed aiming to specify developmental characteristics of these variables to reading comprehension: (1) contributions of prior knowledge should remain fairly stable across all age levels; (2) contributions of phonemic knowledge should account for the largest portion of the variance at beginning reading levels (ages 6-7) and decrease to significantly smaller amounts at higher reading levels (ages 10-12); and (3) listening comprehension contributions should increase across the 3 reading levels and rival the contributions of prior knowledge at the highest reading level. Subjects were 1200 children ages 8 to 12 years who were the normative sample of the Kaufman Assessment Battery for Children. Findings provide support for developmental shifts for phonemic knowledge as predicted. However, the contribution of prior knowledge diminished from 35-47% at the younger ages to approximately 3% of the variance at age level 10-12; while listening comprehension increased dramatically across the age levels, going from 6% at age levels 6-7 to 60% at age levels 10-12. (Contains 14 references and a table of data.) (Author/RS)