Several research studies linking early phonemic awareness to the prevention of later reading difficulties strongly suggest that phoneme segmentation and blending, rather than rhyming and alliteration abilities, are the key aspects of phonemic awareness that are related to the prevention of difficulties. Yet there is a persistent belief among many educators that instruction in rhyming and alliteration are adequate to develop phonemic awareness and developmentally more appropriate than segmentation and blending activities. Using quasi-experimental methods, I evaluated two approaches for teaching phonemic awareness to 4- and 5-year-old children in four Head Start classrooms. The first approach focused on rhymes, alliteration, and story activities. The second approach focused on phoneme segmentation and blending in the context of sounding out actual words. Results showed that children taught using the second approach produced significantly greater gains in phonemic awareness and letter-sound knowledge, compared to children using the first approach. Both approaches were more effective when teachers had previously taught attention skills to their children.