When global positioning system (GPS) signals propagate through the ionosphere, they experience an extra time delay. The ionospheric delay can be estimated using L1/L2 GPS measurement. In order to mitigate the pseudorange multipath effect on real-time ionospheric delay estimation, the multiday multipath template technique has been developed. The algorithm permits the pseudorange multipath error for a specific day to be corrected using the generated multipath template. Data from National Chengchi University, in Taiwan was used to test the application of the multipath template to real-time ionospheric delay estimation. Test results indicate that: (1) The performance of the various 5 day multipath templates is better than that of other multiday multipath templates and (2) the multipath template technique is an effective method to mitigate the GPS pseudorange multipath and should be implemented at reference stations within local-area differential GPS, wide-area differential GPS, and wide-area augmentation system networks, GPS deformation monitoring networks, etc.