In a qualitative, multiple case study, we explored the challenges and successes teachers encounter while participating in a professional development program aimed at improving their reading comprehension instruction so as to increase students' self-regulated use of comprehension strategies. We documented five fifth grade teachers' experiences as they participated in a year-long professional development program. Teachers frequently faced obstacles related to texts, classroom management, instructional decisions, their students, time, and assessment issues. However, the teachers reported positive changes in their thinking and reading comprehension instruction. We also observed growth in their students' reading comprehension behaviors, with some students reaching the self-control level of self-regulated use of comprehension strategies as the year proceeded. (Contains 1 footnote.)