More than 400 varieties are known in avocado and they are classified into 3 distinct horticultural or ecological races: Mexican, West Indian and Guatemalan. They may be recognized as subtropical, semi-tropical and tropical. Each race is identifiable by their unique characteristics like fruit size, peel, texture and maturity date. The varieties of Mexican race are characterized by anise-scented leaves, small fruits, thin glossy skin, high oil percentage and large seeds. West Indian and Guatemalan races lack leaf scent and bear moderate to large fruits. Like Mexican race, fruits of West Indian race mature in 6 months and contain large seed with loose cavity, while Guatemalan fruits mature in 9 months and have smaller seed and tight cavity. West Indian cultivars have generally fruits with smooth leathery skin and those of Guatemalan possess coarsely granular skin

Some of the well-known cultivars of these 3 races are as follows:
1. Mexican—Gottfried, Duke, Pernod
2. West Indian—Pollock, Simmond, Black Prince, Fuchsia, Peterson, Waldin
3. Guatemalan—Taylor, Linda, Queen, Itsamma, Benik. .

Many cultivars of commercial significance are hybrids of these 3 races. They are Fuerte, Collinson, Winslowson, Fair child and Long. The most leading avocado cultivar in the world Fuerte, a Mexican × Guatemalan hybrid, bears pear-shaped fruits each weighing on an average of 400g with a smooth, thin, dull green skin and a tendency towards alternate bearing. The pulp has a buttery texture, a rich nutty flavour and contains oil up to 26%. Nabal, Hass, Lyson, Dickinson, Linda, Pollock and Waldin are some important cultivars of California and the coastal Florida. Sri Lanka grows mainly Trapp, Pollock, Dickinson, Duttan, Lyon, Mayapah and Gottfried.

In parts of south India and Maharashtra where avocado is successfully grown, 2 varieties; Purple (West Indian race) and Green (Guatemalan race) are popular. Purple variety bears pear-shaped fruits with a long neck weighing about 450g. The fruits have smooth, moderately thick, leathery skin and the pulp is firm, deep yellow, fine in texture with a rich and nutty flavour. The fruits of Green variety are oval to obovate, large (450–680g) with a rough, moderately thick, brittle skin. The flesh is soft, greenish-yellow with a mild nutty flavour. Single trees of avocado are not productive at times. For want of pollination, hence, while raising a plantation in new area, mixed planting of cultivars is desired instead of mono-clonal stands.