Complete homozygozity in Coffea arabica L. (2n = 44) has been achieved through doubling of the chromosomes of a dihaploid plant (2n = 22). From its otherwise normal progeny, three offspring were separated because of their resemblance to the phenotypes monosperma, murta and angustifolia. The first one (monosperma) had 2n = 22 chromosomes and thus seems to be originated through parthenogenesis, the known origin of monosperma in Coffea. The second mutant, has 2n = 43 chromosomes. The third (angustifolia) mutant was also a monosomic (2n = 43). Since the angustifolia phenotype is due to a pair of genes ag ag, and since some angustifolia are of difficult genetic analysis, a suggestion is made that the late are monosomic. Cytological analysis of same proved that at least three of six examined are monosomic. It is expected that new types of monosomies will be found, as well as trisomies. The selfing of monosomies may give rise to nullisomics which will be of value in the making of a genetic map for coffee.