Disclosed are a positive active material composition for an electrochemical device, a positive electrode, and an electrochemical device including the same. The positive active material composition includes: a carbon-based additive including a hydroxyl group (—OH) and an enol group (—C═C—OH) on the surface, having a peak area ratio (OH/C═COH) of a hydroxyl group peak area and an enol group peak area of an infrared spectroscopy (FT-IR) spectrum ranging from about 0.5 to about 10, having a specific surface area of about 50 m2/g to about 3000 m2/g, and having an oxygen-containing heterogeneous element in a content of less than about 15 wt %; a positive active material; a conductive material; and a binder.