Concrete block according to SNI 03-0691-1996 "It is a combination of materials made from a mixture of portland cement or hydraulic adhesives or hydraulic adhesives such as water and aggregates with or without other added ingredients that do not reduce the quality of the concrete bricks". The test of this research is determine the addition of snail shells as an additional material for fine aggregate to the compressive strength of concrete blocks. From the compressive strength test carried out on cube specimens, the results obtained were 21.07 MPa for the test object 0% or normal with an average water absorption capacity of 2.71% , For the test object with the addition of 20% snail shell fraction, the compressive strength test was found to be 17.88 Mpa and the water absorption was 3.42% and finally for the 50% compressive strength, the compressive strength test was 11.81 Mpa and the water absorption. 3.89%