"First-principles calculations are a research field that allow to solve quantum mechanics equations without using approximate parameters, except for those inherent to numerical algorithms. These calculations are used to obtain theoretically some properties of nanometric structures, like ground-state energies and binding energies with high accuracy. In this work we have presented the results of the interaction between some organic molecules inside a Boron Nitride Nanotube (BNNT). The organic molecules chosen are three amino acids and five nitrogenous bases: glycine, serine, cysteine, cytosine, thymine, uracil, adenine and guanine. The nanotube chosen is a zigzag (12,0) single-walled BNNT. The ground-state energies and the binding energies were obtained using three different approximations: Hartree-Fock, Density Functional Theory (DFT), and DFT-D3, the latter approach was used to take into account the dispersion interactions not present in DFT calculations. The functional used was Becke’s hybrid functional with three parameters and Lee-Yang-Parr (B3LYP), which has been proved to be a good choice for this nanotube because of the agreement with experimental results. In the case of Hartree-Fock approximation, the Basis Set Superposition Error (BSSE) was calculated, because of the error of using a truncated basis set (6-31G). The results show that there is physisorption, i.e., the interaction between the BNNT and the organic molecules is dominated by the van der Waals (vdW) forces. Also, the Density Of States (DOS) was computed and it confirms that there is not chemical adsorption of the molecules inside the BNNT. The computational calculations were developed by using free software licence like: MacMolPlt and Avogadro for build the structures and display the optimized geometries, and GAMESS for geometry optimization and DOS computation."