Abstract. The present study reports the theoretical infrared and electronic absorption spectra of aminoacetonitrile, its ions, cyanoprotonated and aminoprotonated forms in gas phase and astrophysical H₂O ice using quantum chemical method. The second order Mφller-Plesset perturbation (MP2) method with TZVP basis set is used to obtain ground state geometries. An influence of ice on vibrational frequencies of neutral aminoacetonitrile was obtained using integral equation formalism model (IEFPCM). Significant shift in vibrational frequencies for neutral aminoacetonitrile when studied in H₂O ice and upon ionization is observed. Electronic absorption spectra of aminoacetonitrile their ions, cyanoprotonated and aminoprotonated forms are obtained using time dependent density functional method (TDDFT). Vibrational frequencies, dipole moment, electron affinity, proton affinity and ionization potential of neutral aminoacetonitrile in gas phase are in good agreement with the available experimental frequencies at this level of theory. Rotational and centrifugal distortion constants are obtained at this same level of theory. The nature of electronic transitions is identified. We suggested lines especially good to be observed experimentally to detect these molecules in interstellar medium. Difference in spectroscopic signature of these molecules is obtained which will help in detecting and identifying these molecules in different astronomical environment.