In the picture-word interference paradigm low-frequency words have been shown to induce longer naming times, and thus more interference, than high-frequency words. In this study we used event-related potentials (ERPs) to explore the time course and locus of frequency effects within the language production system. Furthermore, we tested whether frequency effects are related to non-lexical variables such as valence and arousal. We presented pictures and superimposed high and low-frequency distractors and additionally varied the emotional valence and arousal of the distractor words. The effects of distractor frequency in naming times and ERPs - starting at about 300 ms - were modulated by arousal, suggesting that non-lexical mechanisms can modulate distractor effects in the picture-word interference paradigm.