Fungi of the genus Trichoderma spp have been related to the production of hormones or correlated with growth factors, promoting greater efficiency in the use of some nutrients, thus allowing greater availability and absorption by plants. In this context, the objective of this study was to determine the dose of organomineral fertilizer from cupuaçu (Theobroma grandiflorum) residues and the efficiency of Trichoderma harzianum on the initial growth and morphophysiological quality of Mezilaurus itauba seedlings in the northern Amazon. Dose of 50% of the organomineral fertilizer from cupuaçu residues (ORFCup) with Trichoderma harzianum promotes better quality and robustness in Mezilaurus itauba seedlings. The presence of Trichoderma harzianum + 50% ORFCup promotes positive gains in the root biomass of Mezilaurus itauba seedlings. The presence of Trichoderma harzianum promotes an increase in chlorophylls a and b contents in Mezilaurus itauba seedlings. For the production of Mezilaurus itauba seedlings, it is recommended to use Trichoderma harzianum + 50% ORFCup, as it promoted increments in all physiological and morphological indices under the conditions of the present study.