It has been shown (Fischler & Bloom, 1979) that sentence contexts facilitate a lexical decision task for words that are highly likely sentence completions and inhibit the decision for words that are semantically anomalous sentence completions. In the present experiment, the sentence contexts were presented 1 word at a time, at rates from 4 to 28 words/sec. The facilitation for words that were likely sentence completions was marginal at the slower rates and absent at higher rates. In contrast, the inhibitory effects of semantic anomaly were apparent at all presentation rates. Several analyses suggested that the sentence contexts were becoming ineffective at the very highest presentation rates, but the high rates at which the sentence contexts still affected word recognition were taken as evidence that semantic information accrues at an early stage of sentence processing. Implications for Posner and Snyder’s (1975) theory of attention and for models of reading were discussed.