A novel fractional normalised filtered-error least mean squares (FN-FeLMS) algorithm is designed for secondary path modelling in active noise control systems. The update is formed as a combination of the conventional LMS and a fractional update derived from the Riemann-Liouville differintegral operator. The algorithm is considered for (machine) noise reduction for a primary path with zeromean binary or Gaussian sources as inputs. An anti-noise signal is generated to alleviate the effect of noise and to minimise the filtered error by improved secondary path modelling. The proposed arrangement is evaluated for a number of different scenarios by varying the step size and fractional orders. Simulation results show that the proposed technique is more robust to step size variation; it outperforms the traditional FeLMS approach in terms of convergence, model accuracy and steady-state performance for a given signal-to-noise ratio.Introduction: Active noise control (ANC) systems operate by generating a (destructive) interference signal through secondary path models to cancel the effect of noise. ANC can be employed in numerous applications, including personal hearing devices, duct and room acoustics enhancement, engine exhaust noise suppression and improving acoustics in vehicle enclosures, aircraft cabins and vibrating machines [1]. Usually, the filtered-x least mean squares algorithm and its variants are used for ANC problems [2], with computational complexity comparable with the LMS algorithm. An improved version of the algorithm, i.e. filtered-error LMS (FeLMS) is also widely used, for which filtering of the input signal is not required [3] and an adaptive step size strategy is devised to improve initial convergence, whereas noise is reduced in the steady state by reducing the step size [4]. There have been a number of applications of fractional calculus in the recent past in adaptive control and signal processing [5,6]. The main contribution of this Letter is to investigate the use of fractional calculus concepts in ANC systems; both positive and negative fractional orders are employed based on the differintegral operator [6]. A new fractional normalised FeLMS (FN-FeLMS) algorithm, which exploits fractional derivatives, is derived for minimising the mean squared error (MSE).