Site index curves were adjusted for Eucalyptus urograndis stands located in the municipality of Nova Canaã, MT, using the guide curve method. Six mathematical models were tested to estimate the dominant height of the trees according to age and to verify their accuracy for the definition of site indices. The models tested presented similar values with R² values around 0.40 and errors close to 15%, although none presented expressive superiority in relation to the others. The Schumacher model was used for the construction of curves with four classes of site and with amplitude of three meters each. The model was chosen by statistics presented, for the simplicity and adequate estimation of the heights of the trees with only two parameters, presenting the best graphical distribution of the residues