Electrodeposition of amorphous alloys such as NiP, CoP, and NiCoP from acidic solutions containing phosphorous acid as a source of P was investigated. The composition of all electrodeposited alloys depended on current density. An increase in the current density led to a decrease in phosphorus content in the alloy deposit. All electrodeposited alloys exhibited a gradient in composition. Structure (amorphous or microcrystalline) is affected by the composition of alloys. A heat-treatment of amorphous electrodeposited NiP, CoP, or NiCoP alloys led to a formation of crystalline structure, which is a consequence of the decomposition of these alloys to mixtures such as Ni, NixPy, Co, and CoxPy, depending on the alloy electrodeposited.