The developing relation between children's knowledge about the goals and processes of reading, their skills to apply metacognitive strategies, and reading comprehension was examined. Participants were children in third-, fifth-, and eighth-grades in two primary schools in Rijeka, Croatia. All students were Croatian-speaking. A questionnaire of metacognitive reading knowledge and measures of comprehension monitoring during reading were applied in addition to measures of reading fluency and comprehension. Students in the eighth grade manifested better metacognitive knowledge of reading than students in the third and the fifth grades. Multiple regression showed that metacognitive self-monitoring during reading was significant predictor of reading comprehension at all three developmental levels. Besides reading fluency, which explained about 17% of variance, the only significant metacognitive predictor in third-grade students was cloze task, which explained additional 17% of variance, indicating that comprehension monitoring is possible only on the local processing level of reading. In the fifth- and eighth-grade students, self-monitoring played a more important role in reading comprehension than in the third grade. The cloze task and error detection task explained more than 25% of variance of reading comprehension. (Contains 20 references, and 2 tables and a figure of data.) (Author/RS)