The study purpose is to investigate the impact of Business Intelligence within its domains "Data Warehouse, Data Mining, Online Analytical Processing, Report Preparation" in the effectiveness of decision making within it domains "Proper timing of decision making, Ease of implementing the decision, and Accepting the decision from the concerned employee" at the Islamic International Arab Bank.<br /> To achieve the aim of the study, the quantitative descriptive approach was adopted, by comprehensive sampling to collect data. The questionnaire was administrated manually consisting of (28) items on the sample; which consisted of high management mangers totaling (50) managers, all questionnaires were valid for analysis. A set of statistical methods were used to analyze the data, including the mean and simple and multiple regression coefficient through the statistical analysis program (SPSS). Based on the statistical analysis, several findings were concluded, the most important are: - The levels of importance for each of the two domains of Business Intelligence, and the Effectiveness of Decision Making in their domains, in the International Arab Islamic Bank were high for all domains. - There is a significant statistical effect of Business Intelligence on the Effectiveness of Decision Making at the International Arab Islamic Bank. Based on the findings, the study presented several recommendations, those are: - Increasing interest in Business Intelligence in all its domains at the Islamic International Arab Bank; since it has an impact on achieving competitive advantage, through interest in strengthening the infrastructure; and using the best technology; so that Business Intelligence is at the highest level at the bank since there is a large number of competitors in the banking sector. - Enhancing interest in the Effectiveness of Decision Making, because of the sensitivity of decision making, the proper timing for implementing the decision, the ease of implementing the decision, and the acceptance of the concerned employee help to strengthen trust between the decision makers and those affected by the decision, through the participation of subordinates in decisions making through brainstorming sessions; and processes. Persuasion and activating dialogue in the bank to improve transparency.