Longitudinal magnetoresistance measurements on amorphous Fe80-xCrxB12Si8 (x = 0, 2, ..., 12) alloys have been carried out in order to study the effect of chromium and external magnetic fields on these iron-based amorphous alloys. The measurements were taken in external fields up to 45 kOe in various temperatures from 4.41 to 300 K. The slope of the longitudinal magnetoresistance at 4.4 K is found to change sign from negative to positive as x increases and then tends to saturate. We have discussed various possibilities to explain this behaviour and compared our data with those from other chromium-containing amorphous alloys. © 1988.