Studies of Galactic chemical, and dynamical evolution in the solar neighborhood depend on the availability of precise atmospheric parameters (effective temperature Tsubeff , metallicity Fe/H, and surface gravity log g) for solar-type stars. In this work, we use an alternative method based on spectral indices to determine the atmospheric parameters of a sample of nearby FGK dwarfs and sub-giants observed by the MARVELS survey at moderate resolving power. To avoid a time-consuming manual analysis, we have developed three codes to automatically normalize the observed spectra, measure the equivalent widths of the indices, and, through a comparison of those with values calculated with predetermined calibrations, estimate the atmospheric parameters of the stars. Our approach was able to recover the parameters within 80 K for Tsubeff, 0.05 dex for Fe/H, and 0.15 dex for log g, values that are lower than or equal to the typical external uncertainties found between different high-resolution analysis. The results show that the spectral indices are a competitive tool to characterize stars with intermediate resolution spectra.