A program of research was conducted to define the most crucial aspects of print awareness and to develop a tool to measure the resulting construct, validate the instrument, and explore the role print awareness plays in the acquisition of young children's literacy skills. Four basic concepts concerning print that are necessary to give print relevance and utility to children were identified, and a 15-item instrument requiring prereaders to make print-related responses in order to correctly answer questions was developed. The instrument was first administered to a sample of nonreading preschool children in conjunction with interview questions similar to those of Downing (1970, 1972, 1973-74) and Reid (1966). Since item-discrimination indices and internal consistency of the instrument were found to be adequate, the validity of the instrument was then assessed through studies with preschool children of different ages and with second-grade children differing in reading achievement. It was found that performance increased with age and that the test discriminated between levels of reading ability. Two additional studies were conducted to explore possible confounding effects of socioeconomic status and intellectual ability. Findings indicated that the instrument is reasonably reliable and valid. (The relationships between children's print awareness, literacy, and reading achievement are discussed.) (RH)