Introduction: The perception of syllable stress has not been widely studied in developmental dyslexia, despite strong evidence for auditory rhythmic perceptual difficulties. Here we investigate the hypothesis that perception of sound rise time is related to the perception of syllable stress in adults with developmental dyslexia. Methods: A same-different stress perception task was devised and delivered to a sample of 40 adults in two formats, one using pairs of identical 4-syllable words and one using pairs of two different 4-syllable words. Auditory perception of rise time, frequency and intensity, and phonological awareness, phonological memory and reading were also measured. Results: We show that adults with dyslexia performed significantly more poorly in both versions of the stress perception task. Individual differences in the perception of rise time were linked to the accuracy of performance. Conclusions: To our knowledge this is the first direct demonstration of syllable stress perception deficits in dyslexia. The accurate perception of intonational patterning and rhythm may be critical for the development of the phonological lexicon and consequently for the development of literacy. Even high-functioning compensated adults with dyslexia show impairments in speech processing. (Contains 10 tables and 3 figures.)