It is currently held in current consumer behavior literature that consumers have different levels of knowledge and that consumer knowledge acquisition plays an important role in the pre-purchase information search stage. Insight in the information acquisition is a key element in order to understand consumer behavior, and more specific the information search and information processing.In this thesis, insight is gained into the influence of consumer knowledge (objective and subjective knowledge) on the pre-purchase information search behavior and the role of consumer knowledge calibration and involvement. It is focused on the consideration set size, attributes and information source types within the context of Dutch health insurances. This is achieved with the use of a literature study (desk research) and a questionnaire (quantitativeresearch). For the purchase decision of a health insurance, the level of consumer knowledge positively influences the consideration set size (both objective and subjective knowledge), the amount of attributes considered to be important (only subjective knowledge), the importance of price (both objective and subjective knowledge) and the use of memory as an internal information source (only subjective knowledge). The use of impersonal information as an externalinformation source for the purchase decision is negatively influenced by the level of consumer knowledge (both objective and subjective knowledge). The level of consumer knowledge calibration does not play a role in any of these relationships while the level of involvementwith the purchase decision of a health insurance does play a role within some relationships.