The invention relates to agglomerates of flame-retardants, in particular melamine cyanurate, containing aggregates with an average size of between 0.1 and 50μ bonded to each other with the aid of an auxiliary material. This auxiliary material is present in a concentration of between 0.1 and 10 wt. %, relative to the total agglomerates weight, and has a softening point higher than 40° C.The invention further relates to a method for producing said agglomerates, the use of the agglomerates in the preparation of polymer compositions, and polymer compositions containing melamine cyanurate.