Two experiments combined masked priming with event-related potential (ERP) recordings to examine effects of primes that are orthographic neighbors of target words. Experiment I compared effects of repetition primes with effects of primes that were high-frequency orthographic neighbors of low-frequency targets (e.g., faute-faune [error-wildlife]), and Experiment 2 compared the same word neighbor primes with nonword neighbor primes (e.g., aujel-autel [altar]). Word neighbor primes showed the standard inhibitory priming effect in lexical decision latencies that sharply contrasted with the facilitatory effects, of nonword neighbor primes. This contrast was most evident in the ERP signal starting at around 300 ms posuarget onset and continuing through the bulk of the N400 component. In this time window, repetition primes and nonword neighbor primes generated more positive-going waveforms than unrelated primes, whereas word neighbor primes produced null effects. The results are discussed with respect to possible mechanisms of lexical competition during visual word recognition.