An electrophotographic toner composition comprising toner particles containing at least a colorant, a binder resin and an additive, and an image formation method using the toner composition are disclosed, wherein said additive is an additive prepared by surface-treating titanium dioxide fine particles having less than 0.2% by weight of a water-soluble content with a surface treating agent by a wet process. The toner composition is excellent in chargeability, environmental stability of charging, toner admixing properties, and durability. The toner composition hardly adheres to a contact charging member and, even if it does, it causes no reduction in charging performance of the contact charging member and provides a satisfactory image.