Abstract: A rapid method for diagnosing mastitis is described. The method is based on DNA sequence identification comprising the steps of determining the presence of the following DNA sequences in a milk sample: a DNA sequence specific for somatic cells for indicating inflammation; a DNA sequence specific for a mastitis pathogen for indicating infection; and a DNA sequence specific for an antibiotic-resistance-encoding gene of a pathogen for assisting a proper drug therapy. Test kits and genus- or species-specific oligonucleotides and their use in said method are also described.