The effects of the ratio of Y to Dy as well as the effect of Nd and Co substitutions on magnetic properties in [Nd-x(YDy)(0.5(1-x))](2.2)Fe14-yCoyB ribbons melt-spun at 22 m/s have been systematically studied. (Y1-zDyz)(2.2)Fe14B ribbons with a ratio z of 0.25 or 0.5 simultaneously obtains a smaller temperature coefficient of remanence (alpha) and coervicity (beta) which are much smaller than those of Nd-based Nd2Fe14B ribbons. In [Nd-x(YDy)(0.5(1-x))](2.2)Fe14-yCOyB ribbons, Nd substitution (x = 0 to 0.8) can improve the maximum energy product (BH)(max) of annealed ribbons but degrades the temperature stability of the magnetic properties. The ribbons with x = 0.4 and y = 0 yield a (BH)(max) of 8.7 MGOe. For these ribbons, the alpha and beta are -0.07 and -0.31%/degrees C in the temperature range of 27 to 127 degrees C, respectively. Increasing Co (x) from 0 to 3, slightly decreases coercivity H-cj from 21.5 to 16.3 kOe, but keeps the (BH)(max) in the range of 8.6 to 10.2 MGOe. The optimal sample with x = 0.5 and y = 1.5 obtains a (BH) a of 10.2 and 5.0 MGOe at 27 and 250 degrees C, respectively. Its a and beta are -0.11 and -0.30%/degrees C, respectively. These results show that studied ribbons are very promising to develop into high temperature isotropic bonded magnets capable of operating at or above 180 degrees C.