Deficits in error processing may contribute to the continuation of impulsive behaviors such as smoking. Previous studies show deficits in error processing among substance abuse patients. However, these studies were all conducted during affectively neutral conditions. Deficits in error processing in smokers may become more pronounced under affectively challenging conditions, such as during smoking cue exposure. The aim of the present study was to investigate whether smokers showed initial error processing deficits, as measured with the error-related negativity (ERN), and decreased motivational significance attributed to an error, as measured with the error positivity (Pe) when exposed to smoking cues. Additionally, we examined the nature of the ERN and Pe amplitudes in more detail by investigating their associations with trait impulsivity, nicotine dependence levels and cigarette craving. Event-related potentials were measured during a modified Erikson flanker task in both smokers and non-smoking controls. Smokers showed reduced ERN and Pe amplitudes after making an error, accompanied by diminished post-error slowing of reaction times. These results suggest that initial error processing and motivational significance attributed to an error are affected in smokers during smoking cue exposure. Furthermore, individual variation in impulsivity and nicotine dependence was associated with reduced ERN amplitudes.