Experimental evidence indicates that anxious subjects show an attentional bias toward threatening information, but it has also been suggested that cognitive avoidance plays a role in anxiety. It was hypothesized that cognitive avoidance is causally involved in the emergence of attentional bias. An experiment was conducted with normal subjects to investigate whether a strong motivation for cognitive avoidance results in an attentional bias toward the (formerly neutral) subject to be avoided. Forty-five subjects were instructed to suppress all thoughts about numbers, and 45 subjects received control instructions. Both groups carried out a modified Stroop test, including both number words and nonnumber control words. Compared with the control group, the thought suppression group showed an attentional bias toward number words, due to selective allocation of attention to number stimuli. Alternative interpretations, like priming and other unintentional effects of the experimental manipulation, are discussed but do not seem to be plausible. A functional relationship between motivation for cognitive avoidance and attentional bias is proposed.