The purpose of this study is to investigate the difference between the brand selection decisions before and after the ad serving and to examine the impact of attitude, which is owned by the consumer before the ad, to the changes in consumer decisions in the selection of the brand. This study was conducted using causal research design. The sampling method used was non-probabilistic sampling and sample size of 540, consisting of 270 users for brand Pantene and 270 users for brand Rejoice. The results of this study indicate that the attitude of consumers before ad serving had an influence on several changes in the selection decision. This research is important for marketers to continuously understand consumer attitudes, by knowing the type of information on the brand owned by the consumer, the ability of consumer groups in information processing, and the ownership of motivation to process the information.