Magnetostriction of amorphous‐metal alloys has been found to display an unexpected dependence on the glass formers P and B in Fe‐P‐B‐Al. This observation has been used to determine lower values for magnetostriction in the series, Fex(P1−yBy)1−x−.03Al.03 and for the cobalt‐substitued series (FexCo1−x).77P.14B.06Al.03. Samples of these series were produced by the centrifugal quenching technique, and have dimensions of 25 μ in thickness by 1 mm in width. Magnetostriction data was generated using semiconductor gages. Magnetostrictive strain was produced using a stationary sample in the plane of rotation of saturating H‐field of 3 kG. In the first series, Fex(P1−yBy)1−x−.03, the x value was held to within five percent of .77; the y values were allowed to range from .1 to .33. Within the range of y values used a decrease by a factor of 1.5 in y is capable of producing an increase of 1.6 in the magnetostriction. This is exemplified by the +26 μs value for Fe.77P.16B.04Al.03 with y=.2 compared to +16 μs for Fe.77P.14B.06Al.03 with y=.3. The composition Fe.77P.14B.06Al.03 was then used as the basis of a cobalt substituted series, (FexCo1−x).77P.14B.06Al.03. With the glass former proportions now held constant, the magnetostriction values as a function now of x were compared to those of a previously investigated series (FexCo1−x).75P.16B.06Al.03 with y=.27. The curve for the former series remains below that of the latter consistent with the initial observation that the x=1 composition, Fe.77P.14B.06Al.03, with λ=+16 μs has less magnetostriction than the x=1 composition Fe.75P.16B.06Al.03 with λ=+20 μs. While this implies an earlier zero crossing for the magnetostriction of the lower series, the present data seems to indicate that the Fe‐Co amorphous alloys will cross zero at values of Fe of 4% and Co of 96% with only minor variations among various alloy systems.