The present work describes the influence of Al content on the CoCrFeNiAl high-entropy alloys pre-pared by the powder metallurgy technique. The preparation procedure consisted of mechanical alloy-ing and subsequent spark plasma sintering. The content of Al varied from 10 – 30 at.% which affected the microstructure and mechanical properties. Using scanning electron microscope (SEM) and X-ray diffraction analysis (XRD) was found the microstructure becomes more refined with increasing con-tent of Al accompanied by the annihilation of the ductile FCC solid solution (Cr0.25Fe0.25Co0.25Ni0.25) phase and growth of the brittle and hard BCC solid solution phase (α-Fe) and formation of Al(Co0.5Ni0.5) phases, improving the mechanical properties. The best combination of the porosity, hardness HV 30, and ultimate compressive strength (UCS) was achieved for the studied high-entropy alloy when it contained 20 at. % Al.