Abstract: An aqueous heavy duty liquid detergent composition of controlled viscosity is disclosed. The composition comprises a homogeneous mixture of at least one water soluble anionic organic detergent, at least one detergent builder, an oxidized polysaccharide viscosity control agent, an optional salt of an acrylic polymer as a supplementary viscosity control agent, an optional clay fabric softener and water. The composition is characterized as having a considerably lower initial viscosity than compositions which do not contain the viscosity modifier and exhibit a stability or even a diminution of the initial low viscosity after prolonged storage. As a result, heavy duty liquid detergent compositions having good flowability and stability are provided.