A new approach to implement computationally efficient reconfigurable finite impulse response (FIR) filter is presented in this paper. If the coefficients of an FIR filter are decimated by M, i.e., if every Mth coefficient of the filter is kept unchanged and remaining coefficients are changed to zeros, a multi-band frequency response will be obtained. The resulting frequency responses will have centre frequencies at 2πk/M, where k is an integer ranging from 0 to M-1. If these multiband frequency responses are selectively masked using inherently low complex wide transition-band masking filters, different low-pass, high-pass, bandpass, and bandstop filters can be obtained. If every Mth coefficient is grouped together removing the zero coefficients in between, a decimated frequency response in comparison to the original frequency response is obtained. In this paper, we also show the design of a reconfigurable filter bank using the above approach. ©2008 IEEE.