One of the most important construction materials is Concrete, but the use of unreinforced concrete is practically lack due to tightness and weakness facing tensile forces. This great shortage removes by reinforcing steel bars, but in some sections, it is impossible to use fibers to correct the problem. One of the major defects in fiber-reinforced concrete is high porosity, which has a negative effect on the compressive strength of concrete. Also, it creates cracks in concrete which, through time, these micro-cracks rise and threaten the durability of concrete. One of the most efficient and environmentally friendly methods for decreasing pores and cracks in concrete is the use of bacteria in concrete mixing water. Some bacteria in the presence of urea and calcium source have the potential to form calcium carbonate precipitations. In this research has been used polypropylene fibers volume fraction of 0.3% and a kind of bacteria of the Bacillus strain with a concentration of 107 cells /ml in concrete mixing water. Curing the specimens was done, the water containing urea and calcium lactate used at the various ages of 28 and 90 days. Use of bacteria has shown a reduced water absorption in comparison of control specimens. Also, bacteria has reduced the compressive strength of concrete but the use of bacteria and fibers together improves this parameter. The bacteria in the presence of calcium source reduces the porosity of the fiber-reinforced concrete which leads to a reduction in the water absorption.