In the present study, the nature of Dutch children's phonological awareness was examined throughout the elementary school grades. Phonological awareness was assessed using five different sets of items that measured rhyming, phoneme identification, phoneme blending, phoneme segmentation, and phoneme deletion. A sample of 1405 children from kindergarten through fourth grade participated. Results of modified parallel analysis and analyses within the context of item response theory (IRT) showed phonological awareness to be unidimensional across different tasks and grades. Despite the evidence for a single underlying ability, the cognitive task requirements for the various tasks were found to differ. In addition to some overlap between the item sets, those for rhyming, phoneme identification, and phoneme blending were easier than those for phoneme segmentation and phoneme deletion. The results lend support to the assumption that phonological awareness is a continuum of availability for phonological representations which can range from partial availability (i.e., access) to full availability (i.e., access). (Contains 4 figures and 1 table.)