Deposits are like the bloodline for banks as they determine banks' lending capacity and a country's economic savings. However, the existence of a dual banking system poses a challenge to Malaysian Islamic banks competing for deposits. Despite this problem, few investigations were done to comprehensively identify the factors that could help banks attract deposits, particularly for Islamic banks. The purpose of this paper is to fill this gap on deposits of 16 Islamic banks in Malaysia. Secondary data from the bank's annual reports and the Department of Statistics of Malaysia from 2015 to 2019 were analyzed, comprising Islamic Bank Deposits and seven predictors in an empirical model using STATA. The result shows a strong model fit with 92% R squared value that Return on Assets, bank concentration, and Business Enterprise Depositor affect Islamic Bank Deposits positively and significantly while Capital Adequacy Ratio showed negative and significant influence on the deposits. These factors are strongly effective to deposits, significant at 1% level. In contrast, Financing Deposit Ratio and Gross Domestic Product do not significantly influence Islamic deposits. Contrary to economic theory, this study found that an increase in inflation encourages customers to increase their saving deposits in Malaysian Islamic banks. The findings from this study are unique to Malaysian Islamic banks. They indicate important policy implications for Islamic banks practitioners, namely, to increase their focus on business enterprise customers, improve bank's market share and profitability in order to increase deposits while taking advantage of high inflationary period to attract more depositors.