In this study it is argued that a perceiver's regulatory focus (promotion or prevention) influences the amount of attention allocated to processing stimuli from the environment. Results of two experiments, employing an interference task and using different manipulations of regulatory focus, supported this idea. More attention was allocated to stimuli incompatible with the activated focus (promotion-negative stimuli, prevention-positive stimuli). The incompatible stimuli therefore interfered more with an ongoing task than compatible stimuli. These results are discussed in terms of processing efficiency and integrated with motor-compatibility effects.