Using data of the Charge Time-of-Flight (CTOF) mass spectrometer of the Charge, Element, and Isotope Analysis System (CELIAS) on board the Solar and Heliospheric Observatory (SOHO) from ~80 days of observation around solar minimum we derive a value for the Fe/O abundance ratio for the inecliptic solar wind of 0.11¿0.03. Since Fe has a low first ionization potential (FIP) and O is a high-FIP element, their relative abundance is diagnostic for the FIP fractionation process. The unprecedented time resolution of the CELIAS CTOF sensor allows a fine-scaled study of the Fe/O ratio as a function of the solar wind bulk speed. On average, the Fe/O abundance ratio shows a continuous decrease by a factor of 2 with increasing solar wind speed between 350 and 500 km/s. This corresponds to the well-known FIP effect dependence. Our value at ~500 km/s agrees with the previously observed Fe/O ratio in the fast solar wind emerging from polar coronal holes whereas the value for speeds below 350 km/s is consistent with a remote abundance determination in the leg of a coronal streamer. The variability of the Fe/O abundance ratio is much larger in the slow than in the fast solar wind. ¿ 1999 American Geophysical Union