The magnetic properties and microstructures of Misch Metal(MM) - Fe - B and MM-(Fe, Co)-B melt-spun ribbons were investigated. The magnetic properties depended upon the wheel velocity of the single roll, the optimum velocity for good magnetic properties being varied with the composition. MM_(16.25)Fe_(70.06)B_(6.69)Co_7 ribbon which was prepared with a wheel velocity of 20.84m/sec showed a maximum energy product of 4.45MGOe and intrinsic coercive of 8.71KOe in the external field of 20KOe. The microstructure of ribbons melt-spun with the optimum velocities consisted of fine crystalline grains. Magnetic hardening was thought due to these fine grains. The coercive force of MM- Fe - B melt -spun ribbons was decreased by the addition of Co. The velocity showing the highest (BH)_(max) value was rather larger for the Co containing alloy, compared to the Co-free alloy.