Angustifolia mutants have been found in coffee plantations and also among seedlings in nurseries of several varieties of Coffea arabica L. They all present narrow, pointed leaves with few domatias, but may differ in other characteristics and therefore do not constitute a morphologically homogeneous group. Genetic analysis of two angustifolia individuals was made using the typica variety (Coffea arábica L. var. typica Cramer) as a standard. It was found that the main characteristics of each of the two plants were controlled independently by two non-allele, recessive genes, namely ag1ag1 (plant n.° 446), and ag2ag2 (plant n.° RP 104), and that both, reduced yield and vigor of the plants when in a homozygous condition. The genes have complementary effects, for it was found that normal heterozygous Ag1ag1Ag2ag2 plants, when selfed, furnished normal and angustifólia F2 plants in the ratio of 9:7. Crosses of eight other angustifólia individuals with the plants 446 and RP 104 have shown so far that only two of them are also homozygous ag1ag1 and that no other plant is homozygous ag2ag2. Reciprocal crosses, involving some of these angustifólia individuals, gave different results, and angustifólia segregates were found only when these plants entered the crosses as the mother parent. Selfed progenies of these angustifólia mutants comprised normal and angustifólia seedlings in the aproximate ratios of 2:1 and 9:7. One selfed progeny presented only normal seedlings. A suitable explanation for the abnormal ratios here reported still remains to be found.