Abstract. The activation of semantic categories has often been claimed to occur in an attention-free, unconditionally automatic fashion (e.g., Bargh & Chartrand, 1999 ; Ferguson & Bargh, 2004 ). Using a dual-task procedure we tested whether the activation of valence categories is restricted by dual-task specific attentional limitations. For this reason we implemented a modified Eriksen-flanker task as Task 2 in a psychological refractory period paradigm. Participants were to judge the frequency of a tone in Task 1 and the valence of a target word in the presence of irrelevant flanker words in Task 2. Two different flanker categories ensured the activation of semantic categories instead of S-R based response activation. The most important result was an underadditive interaction between flanker congruency and the amount of temporal overlap between tasks that was independent of flanker type. Following the locus-of-slack logic, we interpret these findings as evidence for Task 2 processing parallel to bottleneck-stage processing in Task 1. This extends previous findings by showing that not only number categories ( Fischer, Schubert, & Miller, 2007 ; Oriet, Tombu, & Jolicouer, 2005 ), but also semantic valence categories can be activated despite dual-task capacity limitations.