Two experiments examined the effect of semantic interference on visual lexical decision (vLD) in normal skilled readers. Experiment 1 employed a dual-task paradigm to test whether nonverbal semantic processing disrupts visual word recognition when the orthographic structure of words and non-words is controlled. Experiment 2 employed the same paradigm to test whether participants strategically shifted their reliance onto orthographic information when orthographic structure provided a cue to lexicality. The results showed (1) significant semantic interference in the vLD task in normal skilled readers when words and non-words were matched for orthographic well-formedness and (2) no semantic interference when words and non-words differed reliably in their orthographic well-formedness. The results are consistent with the view that accurate lexical decisions depend upon semantic activation, especially when judgments cannot be made on the basis of orthographic structure alone. Keywords: semantics; lexical decision; dual-task; dual-route models.