The article presents the results of long-term biochemical analyses of introduced nectarine varieties grown in the humid subtropical zone of the Krasnodar Territory. Physico-chemical studies were conducted at the Subtropical Scientific Center of the Russian Academy of Sciences in the Laboratory of Plant Physiology and Biochemistry. The aim of the work is to identify the characteristics of new and early introduced nectarine varieties characterized by high fruit yields with harmonious taste qualities and resistance to the weather and climate destabilization conditions of the South of Russia. The object of the study is nectarine fruits of different ripening periods: Big Top — early; Orion, Silver Roma, Venus — middle-late; Abundant, Sklor — late. It is noted that the pulp of nectarine fruits is less sweet than that of peaches, richer in organic acids, macro- and microelements, enzymes, vitamins A, B, C, E, K, minerals, saturated and polyunsaturated fatty acids, and contains bio-flavonoids and fiber. The content of ascorbic acid on average by varieties was 6.52—13.26 mg/100 g, the maximum was found in the varieties Big Top (13.26 mg/100 g), Abundant (10.33) and Sklor (11.90 mg/100 g), the minimum was found in Orion, Silver Roma, Venus, which is 1.5—1.9 times lower than the indicators of fruits of early and middle-late ripening periods. This was facilitated by: the peculiarity, age of varieties, weather conditions, water regime, as well as the fact that vitamin C accumulates more in unripe fruits. It was founded that the dry matter content was insignificant (11.03—18.95%), which is used to judge the value of raw materials, in this case, the quality of nectarine fruits, juiciness, storability, transportability, and yield.