17 S PIFFI (SPECTROMETER FOR Infrared Faint Field Imaging) is the new near-infrared field spectrometer for the VLT, developed at the Max-Planck-Institute for Extraterrestrial Physics (MPE, Eisenhauer et al. 2000). Here we report on the results of its first observing runs as a ‘guest instrument’ at the VLT in the February to April 2003 period. As of 2004 on, SPIFFI will be coupled to an adaptive optics module developed at ESO (Bonnet et al. 2003) to provide the SINFONI (SINgle Faint Object Near-IR Investigation) facility. SPIFFI offers imaging spectroscopy of a contiguous, two-dimensional field of 32 32 spatial pixels in the 1.1 – 2.45 μm wavelength range and a resolving power of 1300-3500. As a result, the instrument delivers a simultaneous, three-dimensional data-cube with two spatial dimensions and one spectral dimension. SPIFFI is the successor to the MPE integral field spectrometer 3D, the world’s first infrared integral field spectrometer developed in the early 1990s. When the new generation of 10242 pixels, near-infrared detectors became available in the mid-1990’s, we started the development of SPIFFI, for an order of magnitude increase in the number of spatial and spectral elements over 3D. Even more importantly, because of its fully cryogenic image slicer and high throughput optics, along with OH airglow suppression and smaller pixels, SPIFFI at the VLT delivers a factor of 20 to 50 improvement in point source sensitivity over 3D. This development attracted the attention of ESO, specifically because of its major advantages over long slit spectroscopy when operated together with adaptive optics. Simultaneous observation of a two-dimensional field is the best way to reach the full diffraction limited resolution in imaging spectroscopy, while in addition minimizing slit losses. The development of such an adaptive optics assisted integral field spectrometer was subsequently recommended by the ESO Scientific and Technical Committee (STC) in 1997, and finally formalized in 2001 with a contract between ESO and MPE. Because the research and development program for SPIFFI had been launched long before the official start of the full project, we took advantage of this head start and brought SPIFFI to the VLT as a guest instrument for seeing limited observations, while integration of the adaptive optics module was starting at ESO-Garching.