Biochemistry and haematology are more and more important and sometimes crucial in sport medicine for diagnosing, controlling and preventing purposes. The analytical process and the global laboratory quality are heavily influenced by the preanalytical phase, including biological material collection, identification, storage and transport of the specimen, preparation for analyses of the specimen through centrifugation, freezing and thawing, aliquoting and sampling. The increasing interest of sport biochemistry should be linked to a knowledge of principal problems and pitfalls in the preanalytical phase of various parameters, commonly used in following training, diet, and performances of athletes, to avoid misinterpretation of data and to improve usefulness of biochemical investigations. We prepared a practical review of preanalytical aspects of principal analyses applied to the athletes. We include the choice of anticoagulant and its limits for haematological tests, the preparation and manipulation of specimens for hormonological investigation, especially for labile molecules, and for cardiac markers, lactate, cytokines, micronutrients, antioxidant molecules. Preanalytical phase of specimens different from blood are also showed, including urine and saliva, and some aspects of preparation of materials to be analyzed with molecular biology technology are treated. Stability of some analytes, when the parameter is fundamental for the clinical usefulness of the results, is supplied. Preparation of the subjects, however, including the possible influence of physical exercise and biological rhythms on the biochemical and haematological parameters, are not listed.