In regard to the knowledge of provoking a worldwide resistance against antibiotics due to incorrect application and the resulting uptake of residues via the food chain, the European Union set maximum residue levels (MRLs) for these substances in animal derived products to protect the customers. In respect of these MRLs a multi-class UHPLC-MS/MS multiclass method has been developed for the simultaneous determination of 30 substances from different compound groups (quinolones, macrolides, lincosamides, β-lactams, sulphonamides, diamino-pyrimidine derivates and tetracyclines) in various kinds of dairy products. Since this method should be suitable for routine laboratory use, sample preparation requires an easy and fast approach to ensure high sample throughput. Therefore a sample preparation with C18EC dSPE bulk sorbent as a combination of the easy and quick sample preparation provided by QuEChERS and the clean-up principle of reversed phase SPE was applied. This method was validated for all compounds in all matrices in compliance with the requirements of Commission Decision 2002/657/EC.