An anionic surfactant particle for use in laundry detergent compositions has an anionic surfactant content of at least 95 wt % of anionic surfactant and comprises linear alkylbenzene sulphonate (LAS) and primary alcohol sulphate (PAS) in a weight ratio of from 5:1 to 1:3. The particle, which is preferably in the form of a flake, is of low hygroscopicity and dissolves rapidly in water.