The present work describes the influence of Al content on the CoCrFeNiAl high-entropy alloys prepared by the powder metallurgy technique. The preparation procedure consisted of mechanical alloying 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 grain refined with increasing content 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.