This document encompasses the determination of the fatty acid profile in algae and algae products, thereby including micro- and macroalgae, according to the definitions adopted by CEN. This determination enables that all fatty acids present at a significant level (> 1 % of the total fatty acids) in the algal matrix are quantified in an accurate and reproducible way. The concentration of each fatty acid will be available in relative (in %) and, by means of an appropriate internal standard, absolute (mg/g dw) terms. Moreover, the method described in this standard ensures a practical and safe technical approach, whose protocol details and all related know-how will be easily and economically transferrable to all the sector stakeholders. This document ensures this objective by a comprehensive and fully detailed description of all technical steps from the sample itself (including its state and form) to the gas chromatographic technique and the calculation of the fatty acid content. The wording avoids any risk of ambiguity or wrong interpretation. Finally, this methodological standard will be informed by other equivalent standards applied to other matrices and will take into account other standards concerning specific treatment or extractive procedure of the sample prior to the fatty acid analysis itself.