This paper presents a sensitivity analysis of neural network (NN) parameters to improve the performance of electricity price forecasting. The presented work is an extended version of previous works done by authors to integrate NN an similar days (SD) method for predicting electricity prices. Focus here is on sensitivity analysis of NN parameters while keeping the parameters same for SID to forecast day-ahead electricity prices in the PJM market. Sensitivity analysis of NN parameters include back-propagation learning set (BP-set), learning rate (eta), momentum (alpha) and NN learning days (d(N)N). The SD parameters, i.e. time framework of SD (d = 45 days) and number of selected similar price days (N = 5) are kept constant for all the simulated cases. Forecasting performance is carried out by choosing two different days from each season of the year 2006 and for which, the NN parameters for the base case are considered as BP-set = 500, eta = 0.8, alpha = 0.1 and d(N)N = 45 days. Sensitivity analysis has been carried out by changing the value of BP-set (500, 1000, 1500); eta(0.6, 0.8, 1.0, 1.2), alpha(0.1 0.2, 0.3) and d(N)N (15 30. 45 and 60 days). The most favorable value of BP-set is first found out from the sensitivity analysis followed by that of eta and alpha and based on which the best value of d(N)N is determined. Sensitivity analysis results demonstrate that the best value of mean absolute percentage error (MAPE) is obtained when BP-set = 500, eta = 0.8, alpha = 0.1 and d(N)N = 60 days for winter season. For spring, summer and autumn, these values are 500, 0.6, 0.1 and 45 days, respectively. MAPE, forecast mean square error and mean absolute error of reasonably small value are obtained for the PJM data, which has correlation coefficient of determination (R-2) of 0.7758 between load and electricity price. Numerical results show that forecasts generated by developed NN model based on the most favorable case are accurate and efficient. Copyright (C) 2008 John Wiley & Sons, Ltd.