A novel method for spectral-domain fundamental frequency (F0) estimation is proposed. The basis of this method is estimating F0 using the power spectrum of a windowed speech segment. For this purpose, a new transform is introduced. The prominent feature of this transform is that it estimates F0 from the speech segment power spectrum by exploiting the window function power spectrum. As a result, this transform is named the Window-Based transform. By comparison between the proposed method and the autocorrelation and the cepstral pitch estimation methods, the superiority of the proposed method under noisy environments is demonstrated.