EMIR (Espectrógrafo Multiobjeto Infrarrojo) is a common-user, wide-field, near-infrared camera-spectrograph operating in the near-infrared (NIR) wavelengths 0.9–2.5µm, using cryogenic multi-slit masks. EMIR will be installed at the Nasmyth focus of GTC. It will provide a robust second-generation instrument for GTC while offering unique observing modes in the 10m class telescopes. EMIR is equipped with, among others, three high technology subsystems: the cryogenic robotic slit mask or Configurable Slit Unit ( CSU), the dispersive elements (pseudo-grisms) and the Detector Translation Unit ( DTU). Its Multi-Object Spectroscopic (MOS) mode will allow observers to obtain spectrum of up to 55 objects simultaneously, in the NIR bands Y, J, H, K. The addition of a low resolution standard grism will permit to include the capability of taking multiobject spectra in the YJ and/or HK spectral windows simultaneously.