Olfactory disorder takes a special place among non-motor symptoms of Parkinson’s disease (PD) as one of earliest signs of the disease. Based on literature data, authors suggest that simple and structured tests for detection of olfactory disorders should be part of diagnostic algorithm for early detection of PD) and occupy a special place in differential diagnosis of diseases of the extrapyramidal system. Literature on the methods of study of olfactory function recommended as an additional instrument for PD diagnosis is presented.