The current study focuses on the relationship between alerting and executive attention. Previous studies reported an increased flanker congruency effect following alerting cues. In the first two experiments, we found that the alertness-congruency interaction did not exist for all executive tasks (it appeared for a flanker task but not for a Stroop task). In Experiments 3 and 4, we show that alerting increases the congruency effect in a response selection task only when the relevant and irrelevant information is spatially separated. We suggest that alerting modulates the allocation of attention by prioritizing processing of spatial information presented in the visual field. This process can be adaptive under many circumstances, but it comes at a cost. Alerting could possibly compromise our performance when required to filter out irrelevant spatial information.