Altitudinal distributionand damage intensity of Cypress aphidon Cupressuslusitanicaof different age classes was investigated at SUA Training Forest. Abundance of natural enemies of Cypress aphidat different age classes (young 1-10years, middle 11-25 and old >25years) and altitudinal ranges (lower 1700-1930 m.a.s.l, middle 1931-2125 m.a.s.l and upper 2126-2300 m.a.s.l) was also determined. Systematic sampling was used, whereby every 5 th tree along the row of the study plot/block was considered as a candidate. Five shoots in lower, middle and upper crown part of selected tree were randomly cut and put in labeled zipped plastic bags for laboratory assessment of the aphids and natural enemies. Results from this study indicated that Cypress aphid was un-equally distributed throughout the altitudinal ranges and age classes. The abundance of Cypress aphid per twig was 19.6, 24.9 and 33.7 individuals for lower, middle and higher altitude respectively and was significantlydifferent (p<0.05 and f=6.57). Also the abundance of Cypress aphid was 33.7, 16.6 and 18.8 per twig for young, middle and old age classes, respectively although the abundance was not significantlydifferent (p<0.05 and f=10.82). Mean damage intensity was 37.62%, 22.02% and 27.03% for young, middle and old trees respectively and the differences was significant (p<0.05 and f=7.04). Younger treesat higher altitude were more attacked by Cypress aphid. Three natural enemies namely Pauesiajuniperunum, Hoverfly larvae and Spider miteswere detected on the affected twigs but they were verylow in numbers. Therefore, in order to reduce the damage and spread of Cypress aphid in Olmotonyi, it is recommended that mature trees must be harvested and release Pauesiajuniperunum bio-control agent which has given positive results in Kenya and Malawi. Key words: Cinaracupressivora, Cupressuslusitanica,altitude, age classes and damage intensity.Faculty of Forestry and Nature Conservation under SUA Training Forest