This research was conducted in order to determine the effect of Sodium Silicate (Na2CO3) on the quality of the bricks produced. The concentration used is from 0%, 10%, 20%, to 30% by weight of the cement used. The ratio of brick mixture materials from 1: 7 (cement: sand). Testing of Compressive Strength and Water Absorption of bricks is carried out after 28 days of age, with SNI procedure: 03-0349-1989. The results showed that Sodium Silicate (Na2CO3) with concentrations of 10%, 20% and 30% decreased compressive strength by 45.62 Mpa, 50.27 Mpa and 59.03 Mpa, compared to normal bricks (control). As for water absorption, it has increased by 0.79%, 1.47% and 2.31% compared to normal bricks. This condition can occur because of the physical properties of Sodium Silicate (Na2CO3) which is jelly and sticky, thus affecting the dispersion of water throughout the mixture so that water is not mixed evenly