Serendipity slew survey measurements were acquired with the ISOPHOT C200 detector installed on the ISO mission. The C200 detector is a 2x2 pixel array of stressed Ge:Ga with a pixel size of 89.4arcsec, and was used in conjunction with the C160 broad-band filter (reference wavelength 170{mu}m, width 89{mu}m). During the lifetime of the ISO mission, about 550 hours of measurements have been gathered with more than 12000 slews. From the slew data with low (100{mu}m<=15MJy/sr) cirrus background, 115 well-observed sources with a high signal to noise ratio in all detector pixels having a galaxy association were extracted. The 170{mu}m fluxes measured from the Serendipity slews have been put on an absolute flux level by using calibration sources observed additionally with the photometric mapping mode of ISOPHOT. For all but a few galaxies, the 170{mu}m fluxes are determined for the first time, which represents a significant increase in he number of galaxies with measured Far-Infrared (FIR) fluxes beyond the IRAS 100{mu}m limit.