This thesis explores the field of dollarisation as a macroeconomic instrument to increase domestic and foreign investments. The dollarisation is a pressing issue, especially for countries suffering from high inflation rate and decreasing purchasing power of their national currency. The aim of the study is to investigate whether the dollarisation in Ecuador has had any effects on domestic and foreign investment. The frame of references consists of two parts. In the first part, we present a introduction to the dollarisation concept, the origins and the effects of the implementation. The second part concerns domesticand foreign investment. The determinant factors of expected profitability are presented herein which constitutes our main tool for analysis.