Reconfigurability and low complexity are the two key requirements of finite impulse response (FIR) filters employed in multistandard wireless communication systems. In this paper, two new reconfigurable architectures of low complexity FIR filters are proposed, namely constant shifts method and programmable shifts method. The proposed FIR filter architecture is capable of operating for different wordlength filter coefficients without any overhead in the hardware circuitry. We show that dynamically reconfigurable filters can be efficiently implemented by using common subexpression elimination algorithms. The proposed architectures have been implemented and tested on Virtex 2v3000ff11524 field-programmable gate array and synthesized on 0.18 μm complementary metal-oxide-semiconductor technology with a precision of 16 bits. Design examples show that the proposed architectures offer good area and power reductions and speed improvement compared to the best existing reconfigurable FIR filter implementations in the literature. © 2010 IEEE.