This work deals with the characterization of structure, magnetic and mechanical properties of (FeNiCo)100-x(AlSi)x (x = 0, 5, 10, 15, 25) multicomponent alloys prepared by casting. The results of X-ray diffraction measurements, scanning electron microscopy observations and hardness and magnetic properties investigations are presented. The studies show that cast (FeNiCo)100-x(AlSi)x alloys reveal dendritic morphology and their phase composition depends on (Al + Si) content. For x ≤ 10 a face-centered cubic phase is observed, while the increase of Al and Si content results in a body-centered cubic phase formation. It leads to a fivefold increase of hardness from 88 HV to 526 HV. The investigated alloys have high magnetic induction reaching 170 emu/g, while their coercivity value is even up to 2.9 kA/m for x = 15, and strongly depends on chemical and phase composition.