The paper presents the ELODIE spectrograph, a fiber-fed echelle spectrograph installed at the 1.93-meter telescope of the Observatoire de Haute-Provence. ELODIE is designed to perform accurate radial velocity measurements for the search of brown dwarfs and giant planets orbiting nearby stars. It records a spectrum with a resolution of 42,000 over a wavelength range from 3906 Å to 6811 Å on a 1024×1024 CCD in a single exposure. The instrument uses a tanθ = 4 echelle grating and a combination of a prism and a grism as cross-dispersers. An automatic online data treatment system reduces the spectra and computes cross-correlation functions. The design and performance of ELODIE are detailed, including its efficiency and accuracy in measuring radial velocities. The instrument can measure radial velocities with an accuracy better than 15 m s\(^{-1}\) for stars up to 9th magnitude in less than 30 minutes of exposure time, and for 16th magnitude stars, it can measure velocities with an accuracy of about 1 km s\(^{-1}\). The paper also discusses the instrument's design, data reduction algorithms, and its applications in various fields such as asteroseismology and stellar metallicity measurements.The paper presents the ELODIE spectrograph, a fiber-fed echelle spectrograph installed at the 1.93-meter telescope of the Observatoire de Haute-Provence. ELODIE is designed to perform accurate radial velocity measurements for the search of brown dwarfs and giant planets orbiting nearby stars. It records a spectrum with a resolution of 42,000 over a wavelength range from 3906 Å to 6811 Å on a 1024×1024 CCD in a single exposure. The instrument uses a tanθ = 4 echelle grating and a combination of a prism and a grism as cross-dispersers. An automatic online data treatment system reduces the spectra and computes cross-correlation functions. The design and performance of ELODIE are detailed, including its efficiency and accuracy in measuring radial velocities. The instrument can measure radial velocities with an accuracy better than 15 m s\(^{-1}\) for stars up to 9th magnitude in less than 30 minutes of exposure time, and for 16th magnitude stars, it can measure velocities with an accuracy of about 1 km s\(^{-1}\). The paper also discusses the instrument's design, data reduction algorithms, and its applications in various fields such as asteroseismology and stellar metallicity measurements.