We present PUCHEROS, the high-resolution echelle spectrograph, developed at the Center of Astro-Engineering of Pontificia Universidad Catolica de Chile to provide an effective tool for research and teaching of astronomy. The instrument is fed by a single-channel optical fibre and it covers the visible range from 390 to 730?nm in one shot, reaching a spectral resolution of about 20?000. In the era of extremely large telescopes our instrument aims to exploit the capabilities offered by small telescopes in a cost-effective way, covering the observing needs of a community of astronomers, in Chile and elsewhere, which do not necessarily need large collecting areas for their research. In particular the instrument is well suited for long-term spectroscopic monitoring of bright variable and transient targets down to a V magnitude of about 10. We describe the instrument and present a number of text case examples of observations obtained during commissioning and early science.