Objectives: The aim was to explore whether word-initial onset awareness is acquired before phoneme awareness and whether onset complexity influences performance on identification tasks. In addition, the relationship between onset and phoneme awareness and letter knowledge was investigated. Method: In this study, 22 monolingual German-speaking preschool children aged 5;00-5;11 were tested. Onset, phoneme identification, and letter knowledge tasks were administered. The children were presented with pictures of word pairs. Both words in each pair shared a single-consonant onset, a two-consonant onset cluster or the first consonant of a consonant cluster. The children were asked to pronounce the shared sound(s). Additionally, they were asked to name all 26 upper-case letters. Results: Onset awareness tasks were significantly easier to complete than phoneme awareness tasks. However, no influence of onset complexity on onset awareness performance was found. Moreover, letter knowledge correlated with all phonological awareness tasks. Conclusions: The results corroborate that phoneme awareness develops already at preschool age irrespective of explicit literacy tuition. Nevertheless, letter knowledge is closely related and should be linked to onset/phoneme awareness tasks. © 2014 S. Karger AG, Basel