The present invention relates to a filler composition comprising a) a filler, b) a cationic inorganic compound, c) a cationic organic compound, and d) an anionic polysaccharide, wherein the filler is present in an amount of at least about 1% by weight, based on the total weight of the composition, the anionic polysaccharide is present in an amount of about 1 to about 100 kg/ton, based on the weight of filler, and wherein the composition is substantially free from fibers. The invention further relates to a filler composition comprising a), b), c) and d) as defined above wherein the filler is present in an amount of at least about 1% by weight, based on the total weight of the composition, the cationic inorganic and organic compounds are each present in an amount of from about 0 to about 30 kg/ton, based on the weight of filler, whereby the composition comprises at least one of the cationic inorganic and organic compounds, and the anionic polysaccharide has a degree of substitution of net anionic groups of up to about 0.65. The invention further relates to a method of preparing a filler composition comprising mixing a), b), c) and d) as defined above. The invention further relates to a filler composition obtainable by the method, use of a filler composition as an additive to an aqueous cellulosic suspension in a papermaking process, and a process of producing paper comprising adding the filler composition to an aqueous cellulosic suspension. The invention further relates to paper obtainable by the process and paper comprising the filler composition.