Analysis of consumer behavior needs to be studied in a more holistic way to understand what factors lead consumers to buy on impulse. The primary aim of this study was to determine the influence of demographic factors on the Impulse Buying Behavior (IBB) of the consumers of supermarkets. It was aimed to study the impact of demographic factors (age, gender, and income), on the type of IBB (reminder, pure, suggestion and planned IBB). In this research the quantitative research method was used for analysis and getting the results.  The population of this study comprised of consumers in supermarkets situated in Karachi. The samples in this study were those who were shopping at the selected supermarkets in Karachi.  Convenience sampling was used to gather the information from 300 respondents. Descriptive analysis, reliability analysis, and regression analysis were executed using SPSS for testing the stated hypothesis of the study.  The questionnaire was used as a tool for collecting primary data. The results of the study indicated that the Demographic factors significantly influence pure impulse buying behavior and suggestion impulse buying behavior.