Electrodeposited Fe-P amorphous alloy has been characterized in terms of magnetic properties and the microstructure. The Fe-P electrodeposits show amorphous structure with phosphorus contents of about 20 at%. The formation of the amorphous structure depends mainly on the phosphorus content. The amorphous Fe-P alloy shows typical soft magnetic properties such as low coercive force and high permeability. The coercive force (He) decreases with the low temperature annealing, and the lowest He is about 0.05 oersted. This reduction in He can be attributed to structural relaxation. The amorphous phase is crystallized at temperatures above 300 degrees C accompanying a drastic increase in He. The stable crystalline phase is Fe3P.