The main aim for the current paper is to shed some light on some macroeconomic variables that affect the portfolio investment in one of the Middle East countries (Bahrain) for the period 1989-2018. Autoregressive Distributed Lag (ARDL) test was employed. The findings revealed that there was a long run relationship between portfolio and macroeconomic factors. The variable can cause portfolio investment only for consumer price index and gross domestic product in long run. Meanwhile, it found only consumer price index has statistically significant effect with portfolio investment in short-run.