This paper presents a review of short-term hydro scheduling tools reported by the scientific community, presenting different methodologies and models published over the last 20 years about operations, scheduling and optimization of hydro systems, in competitive electricity markets, considering the short-term horizon, i.e., between one day and one week, with the goal of maximizing profits and reducing losses, considering also different hydro configurations around the world. Hence, a comprehensive study is carried out in order to gather the maximum information possible to clarify and show the most recent advances in this field of research, contributing also for the appearance of future contributions.