This investigation examined how cooperating teachers (CTs) influence the behaviors and quality of student teachers' (STs) reading instruction. Improving the reading achievement of early elementary students and enhancing teacher quality are two education reform priorities for Title I schools that have important implications for teacher education. The extent to which new teachers are able to provide effective reading instruction is likely to depend, at least in part, on the quality of reading instruction provided by their cooperating teachers. Eighteen pairs of early elementary CTs and STs were videotaped providing guided reading instruction. Highly qualified observers examined the instructional support behaviors and judged the quality of instructional support provided by CTs during the introductory portion of reading lessons. Correlation analysis revealed a moderate association between the occurrence of specific reading instruction behaviors and observers' ratings of instructional quality. No differences were found between CTs and STs for the frequency of reading instruction behaviors (e.g., support for fluency and phrasing). CTs, however, seemed to provide a higher quality of meaning support, but no other differences in behavior or quality were found. CTs' instructional behaviors were predictive of ST instructional behaviors, but STs' quality was unrelated to either CT instructional support behaviors or quality of instructional support. These findings seem to suggest that additional measures, beyond exposure to a cooperating teacher, should be undertaken to improve the quality of reading instruction provided by student teachers. Discussion focuses on implications for teacher preparation and earlier career teachers, and for partnerships between school districts and universities. (Contains 5 tables and 1 footnote.)