The synthesis of Mannich bases is simple and facile. High reactivity and great possibility for practical application allow us to increase its variety and realize diverse chemical conversions [1,2]. This paper presents the results of studies cycloalkylation of phenol and p-cresol with 1-methylcyclopentene, 1-methylcyclohexene, diprene and dipentene in the presence of a catalyst – zeolite-Y impregnated with phosphoric acid to produce cycloalkylphenols. Based on the synthesized cycloalkylphenols, 2-hydroxy-3 (5) -cycloalkylbenzylphenylamines were obtained. The reaction of phenols interaction with 1-methyl cyclopentene, 1-methyl cyclohexene, diprene and dipentene has been studied at temperature 60-130°C, reaction duration 2-6 hours, phenol to cyclone mole ratio 0.5-h 1:3, catalyst amount 5-20% of taken phenol. Under the established optimum conditions the main products acceptable yield is 73.4-89.6%. The reaction of 2-hydroxy-3(5)-cycloalkylbenzylphenyl amines synthesis was performed by cycloalkylphenols interaction with formaldehyde and aniline at temperature 75-90 °C. In that case the main products yield amounted to 73.4-88.6%. After 3-hydroxy-3(5)-cycloalkylbenzylphenyl amines treatment their chemical structure has been confirmed by IR and MR spctroscopic methods.formulaThe cycloalkylbenzylphenyl amines synthesized have been tested as an additive to motor oil. The oil stability has been studied in accordance to GOST 11063-77 at temperature 200°C, duration 10-20 hours, additive amount 0.5-1.0%. The results of the researches carried out show that cycloalkylbenzylphenyl amines synthesized may be used as an efficient antioxidative additives to motor oils.