The paper describes the heat treatment of precipitation hardening aluminum alloys and its impact on the microstructure and properties of alloys. By choosing the heat treatment parameters, different values of the obtained test parameters, as well as the obtained microstructures are achieved, which significantly affect the quality of the achieved state of the material. In the experimental part, the hardness and corrosion resistance of aluminum alloy AlSi1MgMn samples that were differently heat treated were determined. Heat treatment consisted of homogenization annealing and artificial aging, with varying cooling parameters and also varying temperature and time of the artificial aging. Hardness testing after artificial aging gave a range of hardnesses, with the highest value of 146 HV1, while the lowest was 90 HV1. Electrochemical tests showed that on all testing speciments significant pitting corrosion in aqueous 3,5 % NaCl solution has appeared, with destruction of the passive film shortly after the aluminum alloy was in contact with the solution. By the microstructure analysis the preffered state of the alloy was determined, where small precipitation particles are homogeneously distributed in the aluminum matrix. The presence of pores and microcracks at the magnifications greater than 500x is visible. The highest corrosion resistance and increased hardness was achieved after solution annealing, cooling into water at 50 °C and with artificial aging parameters 150 °C/10 h/air.