<p>The genetic diversity of Cocos nucifera L. is described, based on historical, and ethnobotanical studies and it is evaluated by analyzing patterns of morphological variation of fruit, variation in morpho-physiology of plants and leaves, and iso-enzyme polymorphism. Genetic structure of populations was analyzed and evaluated in relation with Lethal Yellowing disease for seven years. The diversity includes four ecotypes of tall coconut: 'Atlantic Tall', 'Pacific Tall l ', Pacific Tall 2', and 'Pacific Tall 3', and one ecotype of dwarf coconut: 'Malayan Dwarf'. Results suggest several early introductions of tall ecotypes to Mexico that were already differentiated. The genetic distance observed between Mexican populations and recently imported ecotypes suggest that the 'Atlantic Tall' originated from the west coast of Africa, while the 'Pacific Tall' ecotypes originated in the Pacific Islands, the 'Malayan Dwarf' ecotype provenances from South-East Asia. Levels of diversity in the Mexican population were similar to those of the area of New Guinea and to the collection of<br />the Ivory Coast. The diversity found was exposed to Lethal Yellowing disease over a period of seven years. The 'Atlantic Tall' ecotype showed a high susceptibility, the 'Pacific Tall 3' medium susceptibility, the Pacific Tall 1 and 'Pacific Tall 2' medium resistance while the 'Malayan Dwarf' showed high resistance. It is necessary to implement a program of conservation for the ecotypes 'Atlantic Tall' and 'Pacific Tall 3', and to initiate a breeding program of crosses between 'Pacific Tall 2' with 'Malayan Dwarf' aimed at obtaining genotypes<br />resistant to Lethal Yellowing disease which will increase productivity.</p>