In the present study, we investigated critical factors in letter-sound acquisition (i.e., letter-name knowledge and phonological awareness) with data from 653 English-speaking kindergartners in the beginning of the year. We examined (a) the contribution of phonological awareness to facilitating letter-sound acquisition from letter names and (b) the probabilities of letter-sound acquisition as a function of letter characteristics (i.e., consonant-vowel letters, vowel-consonant letters, letters with no sound cues, and vowel letters). The results show that letter-name knowledge had a large impact on letter-sound acquisition. Phonological awareness had a larger effect on letter-sound knowledge when letter names were known than when letter names were unknown. Furthermore, students were more likely to know the sounds of consonant-vowel letters (e.g., "b" and "d") than vowel-consonant letters (e.g., "l" and "m") and letters with no sound cues (e.g., "h" and "y") when the letter name was known and phonological awareness was accounted for. Sounds were least likely to be known for letters with no sound cues, but reliable differences from other groups of letters depended on students' levels of phonological awareness and letter-name knowledge. (Contains 7 tables, 2 figures, and 3 footnotes.)