Phonological awareness is a critical enabling skill in learning to read, often developed outside the context of formal reading instruction. More than 2,000 6-year-old children were tested on phonological awareness at two occasions during the preschool year in two cohorts. Between the assessments, a training program was implemented. A two-level path model was applied. More frequent training sessions were connected to higher gains of test scores especially for children with low initial scores in the first cohort. A clear gender effect was also observed. There were more boys with very low initial scores and more girls among the top scorers. A clear SES-effect indicated the influence of early language stimulation. Children who already at the beginning of the preschool year had grasped the alphabetic code had the highest initial scores on the test.