AbstractThe dynamics of accumulation of mono‐and sesquiterpenes in leaves and fruits of a mandarin (Citrus unshiu Marc.) during ontogenesis was studied. Limonene, linalol, p‐cymene, β‐elemene are found to accumulate intensively in fruits prior to ripening. From that time till the physiological maturity of fruits, the biosynthesis of γ‐terpinene, β‐elemene and especially that of limonene increases, while the content of linalol, β‐caryophyllene, p‐cymene and α‐terpineol decreases. From the beginning of time of blossoming until the commencement of fruit ripening, the content of γ‐terpinene and p‐cymene varies essentially in leaves. From October the content of mono and sesquiterpenoids decreases sharply and remains practically unchanged during the forced state of rest.