Abstract. The aim of this study was to verify the effects of irrigation and fertirrigation on the wood technological properties of the hybrids of Eucalyptus urograndis (Eucalyptus urophylla x Eucalyptus grandis) and Eucalyptus grancam (Eucalyptus grandis x Eucalyptus camaldulensis), aiming at the production of cellulose and charcoal. Analyses were carried out with a completely randomized experimental design, arranged in a factorial scheme with two factors: hybrids (Eucalyptus urograndis and Eucalyptus grancam) and irrigation (fertirrigated microaspersion, microaspersion, fertirrigated drip irrigation, drip irrigation and control treatment). Basic wood density, insoluble lignin content, total extractive content, holocellulose, ashes and morphological characterization of the fibers were analyzed in four trees per hybrid at 45 months. The effect of the interaction hybrid x irrigation was significant at 5% probability for the analyzed variables, with the exception of the insoluble lignin content and the Runkel index. Irrigation and fertirrigation did not influence the basic wood density and the insoluble lignin content of Eucalyptus urograndis. The total extractive content was reduced with the application of fertirrigation. In general, there was no influence of silvicultural treatments on fiber size. Given the results presented, it has been concluded that Eucalyptus grancam presents greater sensitivity to the application of irrigation and fertirrigation, which can be applied to both hybrids, Eucalyptus urograndis and Eucalyptus grancam, without damaging their technological properties.