The genesis of higher alkyltoluenes with a normal alkyl chain (n-ATs) has been studied. The conditions for their formation from both individual C-18 (oleic and stearic) fatty acids and C-14 alcohol in the thermocatalytic mode and from Tasmanites planktonic algae during noncatalytic thermal treatment have been considered. The feasibility of the formation of n-ATs has been confirmed by determining their composition and structure.