The use of seaweed polysaccharides for fine chemical synthesis is a promising approach to replace fossil fuelbased feedstocks. In this work, acid-catalyzed pyrolysis of the polysaccharide iota-carrageenan from red seaweed has been studied using differential scanning calorimetry (DSC). DSC shows that sulfuric acid in a polyethylene glycol (PEG) solvent lowers the temperature of the exothermic decomposition peak by ca. 63 ◦C when compared with the pyrolysis of pure polysaccharide. Evolved products from the pyrolysis in a purpose-built glass tube vacuum reactor were analyzed using gas chromatography/mass spectrometry, and showed that levoglucosenone (LGO) and furfural were dominant. Yield of LGO was 12 mg/gIC or 9.0 mol% and of furfural was 2.8 mg/gIC or 2.8 mol% when 2% w/w H2SO4 was used as catalyst.