Microalgae are a very diverse group of microorganisms with great potential for biotechnological applications. To best exploit these organisms is necessary to expand our knowledge at its molecular levels. To realize these studies, however, it is essential to have efficient and reproducible methods for total RNA isolation. The objective of this research was to develop a method for high-quality total RNA isolation from three oleaginous microalgae species promissories for biotechnological applications. Three strains Ankistrodesmus sp., Chlorella sp., and Scenedesmus sp. were cultured on CHU-10 medium. Then, were harvested by centrifugation and total RNA was isolated with three commercial kits, one previously published method, and our improved CTAB-LiCl method. Quality and quantity of total RNA isolated were assayed with standard spectrophotometric and electrophoretic techniques. The highest quality (A260/A280: 1.95-2.02, A260/A230: 1.12-1.84) and yield (16.40-93.63 μg/g fresh weight) of total RNA from the three microalgae strains were obtained with our improved CTAB-LiCl method. In addition, the time required to complete the isolation process and the cost were relatively lowest. In conclusion, the improved CTAB-LiCl method, in contrast to frequently used commercial kits, and a previously published method, is effective and reliable to produce total RNA of high quality and quantity that is suitable for cDNA synthesis and polymerase chain reaction.