We report an independent spectral classification of a sample of poorly studied M-dwarf candidate stars observed with the OSIRIS instrument at GTC. Our project was carried out as an independent test of the spectral classification. It is crucial for the studies of extrasolar planets orbiting M-dwarfs, since properties of the host star are directly related to understanding the planet properties and possible habitability. Understanding of the statistical properties of the dwarf stars is also crucial for the Simple Stellar Population models that play a major role in the modern astrophysics. Ha emission was detected in 33% of the sample with evidence of Ha variability in one object.