The purpose of this study was to explore whether there was a significant correlation between vocabulary and reading comprehension in terms of text types as well as whether the vocabulary was a predictor of reading comprehension in terms of text types. In this regard, the correlational research design was used to explain specific research objectives. The study was conducted in Ankara-Sincan during the 2008-2009 academic years. A total of 120 students having middle socioeconomic status participated in this study. The students in this research were in the fifth-grade at a public school. Reading comprehension and vocabulary tests were developed to evaluate the students' reading comprehension and vocabulary levels. Correlation and bivariate linear regression analyses were used to assess the data obtained from the study. The research findings indicated that there was a medium correlation between vocabulary and narrative text comprehension. In addition, there was a large correlation between vocabulary and expository text comprehension. Compared to the narrative text comprehension, vocabulary was also a strong predictor of expository text comprehension. Vocabulary made more contribution to expository text comprehension than narrative text comprehension.