Using as examples either common or important but less frequent bacterial skin diseases, detailed practice-oriented information is provided on microbiologic diagnostic procedures. Despite the availability of many advanced techniques, often the simplest measures can provide the correct diagnosis and help guide therapy. The practicing physician must also know what is required for more advanced diagnostic procedures; if they are used improperly, unnecessary costs accumulate. Conversely, the decision process and technical methods must be understandable for those without special background in microbiology. The value of all methods is discussed from the perspective of dermatology with emphasis on appropriate sampling and handling of specimens.