The role of properties of attitude-relevant knowledge in attitude- behavior consistency was explored in 3 experiments. In Experiment 1, attitudes based on behaviorally relevant knowledge predicted behavior better than attitudes based on low-relevance knowledge, especially when people had time to deliberate. Relevance, complexity, and amount of knowledge were investigated in Experiment 2. It was found that complexity increased attitude- behavior consistency when knowledge was of low-behavioral relevance. Under high-behavioral relevance, attitudes predicted behavior well regardless of complexity. Amount of knowledge had no effect on attitude- behavior consistency. In Experiment 3, the findings of Experiment 2 were replicated, and the complexity effect was extended to behaviors of ambiguous relevance. Together, these experiments support an attitude inference perspective, which holds that under high deliberation conditions, people consider the behavioral relevance and dimensional complexity of knowledge underlying their attitudes before deciding to act on them.