To understand the relationship between the electronic structure of amphetamines and their biological activity, a computational investigation was carried out to characterise the 17O and 14N, electric field gradient (EFG) tensors and nuclear quadrupole coupling constants (NQCC) as well as 17O, 15N, 13C and 1H chemical shielding tensors of amphetamines. Calculation were performed with the B3LYP and PW91P86 density functional theory (DFT) methods with the 6-311++G(d,p) basis set. The anisotropic (Δσ) and isotropic (σiso) shielding are in good agreement with the available experimental data. The results indicate that the EFG and σ at oxygen are insensitive to substitution at the N and C10 positions in amphetamines. In contrast, the nitrogen EFG and σ are quite sensitive towards substituent changes. Furthermore, it was found that EFG tensors are more sensitive than σ tensor to the electron density distribution in amphetamines. Biological activities of amphetamines were found to depend upon the electron density distribution in the region of N atoms.