Abstract The effect of equal channel angular pressing (ECAP) and post-ECAP heat treatment on microstructure and mechanical properties of AlSi7Mg0.3 alloy was investigated. The pre-ECAP heat treatment (annealing at 550 °C for 4 hours, water quenching and annealing at 250 °C for 5 hours) was effective in ductility improvement of as-cast alloy state. Repetitive ECAP of the heat treated alloy state at room temperature caused fragmentation and redistribution of eutectic Si-particles and an increase in alloy strength. The post-ECAP annealing for 2 hours at temperature range from 100 to 300 °C initiated gradual decrease in alloy strength and microhardness due to the recovery or recrystallization of solid solution, without noticeable ductility improvement of analyzed alloy.