The purpose of this study was to investigate the relationship of toddlers' vocabulary ability with reading activities and teachers' verbal and nonverbal behaviors during book reading. The subjects were 52 teachers and 104 toddlers at age 2. Lee and Kim (2004)'s categories of the Teachers' Verbal Behaviors, the categories of the Nonverbal Behavioral Analysis(Kim. 2005), and the Peabody Picture Vocabulary Test-Revised (Kim, et al.1995) were used. The data was analyzed by t-test, ANOVA, and Correlations. The results indicated that there were significant correlations in the subcategories of reading activities in classrooms, teachers' picture book reading behaviors, and toddler's vocabulary ability. The toddler's vocabulary ability increased as the ‘interacting time both before and after book reading’ became longer. The toddler's vocabulary ability increased as ‘connecting with previous experience’, ‘asking questions for confirmation’, ‘acknowledging,’ and ‘expanding’ of verbal behavior, as well as the nonverbal behavior, such as ‘requesting behavior’, ‘emotional contact,’ and ‘empathetic behavior.’ In conclusion, teachers' reading behaviors and activities were related to toddlers' vocabulary ability.