This paper represents, a new heuristic algorithm, bat algorithm, is used to optimize filter coefficients in the design of low pass finite impulse response (FIR) digital filter. The FIR digital filters have a wide range of applications due to the features. Bounded input bounded output (BIBO) guarantees stability and is designed to provide linear phase at all frequencies. The bat algorithm is based on the local echolocation behaviors in the nature of the bats, and many areas such as system modeling, image processing and microwave are used. Bat algorithm was used in the design of low pass FIR digital filters for different filter degrees and the obtained results were evaluated in performance analysis.