Advertising is a form of communication intended to convince an audience (viewers, readers orrnlisteners) to purchase or take some action upon products, information, or services etc. Thisrnpaper tried to investigate the relationship between advertising (advertising media, advertisingrnmessage, source credibility, source attractiveness and product personality congruence)rnandconsumer purchase decision of baby diaper by tapping the responses of 380 respondentsrnfrom four sub cities of Addis Ababa City Administration (Bole, Arada, Kirkos&Yeka). To achievernthe objectives of the study, descriptive and explanatory research design were used. Data wasrncollected through questionnaire from a sample of 380 purchasers of disposable baby diaper thatrnwere selected using convenient sampling method. The data collected from the questionnaire werernanalyzed using descriptive statistics (such as mean, standard deviation, percentage andrnfrequency) and inferential statistics like correlation, and multiple regression analysis. Thernfinding revealed that there are positive and significant relationships between advertisingrnmessage, source credibility, advertising media and consumer purchase decision of babyrndiaper.The score of the coefficient correlation determination R2 is 0.655, which implies thatrnthere is quite significant explanatory power and also 65.5% variation on the purchase decisionrnof baby diaper is caused by advertising message, source credibility, advertising media, sourcernattractiveness and product personality match. Eventually, this study recommends appropriaternactions for companies in refining their advertising strategies as a means of overcoming the stiffrncompetition that prevails in the market, therefore, they can increase their sales volume andrnmarket share.