Foreign Portfolio Investment (FPI) plays vital role in prosperity of any economy. The importance of FPI becomes even more crucial when, the subject country is in its developing phase, and in the process of exhausting its resources which are not utilized yet. Moreover, do these factors have similar effect on FPI across counties or not? We have used Multiple Linear Regression Models for China, India, Pakistan and Bangladesh, being emerging economies within the same region to examine FPI's determinants. The study found that GDP growth, External Debt, Population growth, and Inflation are the main factors that affect FPI. Moreover, it is also found that there is different relation of similar factor across the countries, which is due the socio-economic, geographic, and geo-political differences among the subject countries.