Context. There are more than 3000 confirmed and probable known Galactic planetary nebulae, but central star spectroscopic information is available for only 13% of them. Aims. We undertook a spectroscopic survey of central stars of PNe to identify their spectral types. Methods. We performed spectroscopic observations, at low resolution, with the 2-m telescope at CASLEO, Argentina. Results. We present the spectra of 46 central stars of PNe, most of them are OB-type and emission-line stars.