Diagnosis of occupational infectious diseases gives rise to a number of problems in the practice of occupational medicine. Similar symptoms of many infections, including parasitic diseases, can limit the range of applied diagnostic and certification procedures only to diseases induced by pathogenic agents or exposures occurring in the occupational environment. In some cases this makes difficult or even impossible to explain a real cause of patients’ complaints. We present a case report on the patient with suspected occupational borreliosis. Due to many diagnostic doubts during hospitalization, including long term presence of some clinical manifestations reported by the patient, which could occur in the course of borreliosis and also suggest earlier infection by trichinae, a wider span of specialist examinations was applied. Finally, the invasion of trichinae was diagnosed and later confirmed by serologic tests.