This study investigates the effect of experimental temperature on the separation of DNA fragments, 21-587 bp, by both high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE). The results show that the temperature plays an important role in the HPLC separation of DNA fragments. The optimum temperature was found to be between 40 and 50 degrees C for HPLC, while 25 degrees C was the optimum temperature for the CE separation. Also, although CE migration times became shorter, efficiency and resolution decreased with an increase in temperature from 25 to 50 degrees C, but the separation was not significantly affected. Also, the optimum HPLC temperature might be different depending on the fragment sizes to be resolved.