This study represents an exploration into the relationship between comprehension and metacomprehension. The effects of variables known to be sources of reading difficulty were compared on a measure of reading comprehension and one of metacomprehension. One hundred and twenty seventh grade students each read four versions of thirty-six passages which differed in level of familiarity, goodness of structure, and vocabulary difficulty. Then students either rated the comprehensibility of each passage or responded to ten comprehension probes for each of the passages. Both comprehensibility judgments and comprehension performance were positively related to topic familiarity and good story structure. Vocabulary difficulty was negatively related to performance on the comprehension measure only. Implications for research are discussed. �� 1981, SAGE Publications. All rights reserved.