<p>This longitudinal study examines the effects of reading specific genres(fiction,nonfiction,and picture books)on vocabulary growth and reading comprehension skill in elementary school students through two surveys;one at the start of the study and another one year later. Administered to 58 children,the surveys were conducted in the Decembers of their third and fourth grades,respectively. The number of books borrowed from the school library was used as an index of the amount of reading done by the students and the genres of the borrowed books were identified using the Nippon Decimal Classification. Vocabularies and reading comprehension skills were measured using the Reading-Test(Fukuzawa & Hirayama, 2009), which is a standardized test for Japanese students. The results indicated that amount of reading significantly accounted for the variances observed in the childrenʼs vocabulary and reading comprehension scores one year later after controlling for their scores when they were at third grade. Moreover,the amount of reading for nonfiction material significantly predicted gains in reading comprehension skills,although the amounts of reading for fiction and picture books did not.</p>