The paper examines determinants of investment decisions of Estonian companies. Within investment decision determinants the influence of interest rates and cost of capital get special attention as well as the analysis of liquidity constraints. The study is based on answers of questionnaires received from 44 companies of Estonia. Results of the study show that most important determinants of investments are related to risk and uncertainty followed by liquidity constraints and business confidence determinants. Interest rate determinant and cost of capital consideration has small influence to investment decisions as well as have a low profile in overall management focus. Liquidity constraints on other hand should be considered an important decision factor behind investment decisions