This study's aim was to determine the factors affecting Turkish children's reading-writing achievements in the first grade in the preschool period. The prediction level of attention, visual perception (VP), rapid automatic naming (RAN), writing development (WD), and phonological awareness (PA) of the children in the preschool on their success in reading, reading comprehension (RC), and writing in the first grade was investigated longitudinally. In the preschool, 269 kindergarten students participated in the research, 187 out of those who proceeded to the first grade participated the second year of the study. The study was carried out in the screening design. As the result of research, it has been established that VP, PA, RAN, and WD predict the reading rate in the first grade, and that PA and RAN predict the reading accuracy. It has been found out that PA predicts RC and that VP, WD, and PA predict writing.