Analytical laboratories are currently interested in enhancing overall productivity by increasing sample throughput and reducing analysis time. Different approaches are proposed in liquid chromatography (LC) to perform fast or ultra-fast separations with cycle times of less than 5 or 1 min, respectively. Among these approaches, the use of monolithic supports, high temperature LC (HTLC), short columns and ultra-performance LC (UPLC) are described and compared in this study. A comparison of the above LC approaches is presented through Knox curves and pressure plots based on experimental data. Fast separations of pharmaceutical compounds are presented in order to illustrate the interest of these techniques and compare them with conventional LC separations.