This study presents a comparison of biomass production and lipid accumulation of Spirulina platensis grown on a medium prepared with geothermal water (GM) with a synthetic cultivation medium (Zarrouk's medium (ZM)). The biomass concentration of ZM grown algae was found lower than GM3 as 3.7840 gL(-1) and 3.9740 gL(-1), respectively. The lipid content was determined higher for ZM than GM3, 3.2704% and 1.5666%. The fatty acid profiles were almost similar in both media, whereas palmitic acid (C16:0) and arachidic acid (C20:0) were the most abundant saturated fatty acids with gamma linolenic acid (GLA, C18:3, n 6,9,12) being the prominent polyunsaturated fatty acid. The polyunsaturated fatty acid ratio was 41.3657% and the GLA 22.1429% for GM3. It was noteworthy to mention the amount of very long chain fatty acids was 2-fold high in GM3 grown S. platensis. Geothermal water seems to be an alternative substrate for cultivation of S. platensis in order to reduce the production costs with promising sustainable biomass productivity at least by an increase of 3.7% and increase in GLA production.