Abstract In this study, the aging behaviors of high strength low alloyed (HSLA) HC380LA quality steel were investigated. Steel samples were heated in a heat treatment furnace up to 950 °C and kept there for 1 hour, and then quenched in water. Some of the water quenched samples were aged at temperatures between 50–350 °C for 20 min (quench-aged, QA), while the other samples were exposed to the same aging procedure after a 3 % prestraining (strain-aged, SA). Experimental results showed that aging occurred in all QA and SA samples. The highest values for both QA and SA samples were obtained at aging treatment performed at 150 °C for 20 min. When the aging temperature increased to 200, 250, 300 or 350 °C, aging strength decreased. Results of the study suggest that different aging temperatures have an effect on the microstructure and on the mechanical properties of high strength low alloyed steels.