One of the primary issues in handling demands for auto parts in the world is to build a mutual trust between consumers and vendors. When people trust a brand, they purchase more easily and it is possible to develop market. In Iran, there is a growing interest in demand for auto parts and each year, tens of millions of auto parts are getting sold. This paper presents an empirical investigation to detect the effects of brand image on demand for auto parts. Using a sample of 202 randomly selected people who buy/sell auto parts in city of Tehran, Iran, the study determines three variables including brand strength, brand attributes and consumer trust through the implementation of structural equation modeling.