Theories of English phonology regard syllable onset patterns as irrelevant to the assignment of lexical stress. This paper describes three studies that challenge this position. Study 1 tested whether stress patterns on a large sample of disyllabic English words varied as a function of word onset. The incidence of trochaic stress increased significantly with the number of consonants in word onset position. This overall pattern was replicated when various subsets of the database were examined separately, thus demonstrating its robustness and generality. In Study 2, English speakers assigned trochaic stress to disyllabic pseudowords more often when they began with two consonants (e.g., ''plonveen) rather than one (e.g., ''ponveen''). Study 3 examined implications of these results for monosyllabic words and the rhythmic structure of English poetry. An analysis of Milton's "Paradise Lost" found that monosyllabic words beginning with two consonants (e.g., ''stay'') appeared in stressed positions in Milton's verse more often than matched words beginning with one consonant (e.g., ''say''). These studies indicate that syllable weight, and consequently word stress is affected by onset as well as rime structure.