A signaled intersection is an element that is quite important in the transportation system in the city center, one of the intersections in the center of Purwokerto is a signaled intersection of Masjid Street. This intersection consists of four arms, namely the north arm of Ahmad Yani Street, south arm of Masjid Street and east-west arm of General Gatot Subroto Street. Several indicators of the analysis results at the signalized intersection are Degree of Saturation (DS), Queue Length and Delay. The purpose of this study was to determine the effectiveness of the traffic lights and the performance of the intersection with the signal of Masjid Street Purwokerto. The method used to analyze signaled intersections is using the 1997 Indonesian Road Capacity Manual method.From the results of the analysis of vehicle volume data obtained from the Banyumas Regency Transportation Agency, it is found that in 2020 the peak volume on Monday occurs at 06.00 - 07.00 at 2175 pcu. / hour and the degree of saturation (DS) value of 2.26, it can be concluded that the signalized intersection is ineffective. Handling scenario 1 is by changing the signal phase from 4 phases to 3 phases so that the Degree of Saturation (DS) value is 0.69, it can be concluded that the signalized intersection condition becomes effective. After analysis in 2025, the degree of saturation (DS) value is 3.05, so the condition of the signalized intersection can be concluded ineffective and scenario 1 is carried out by changing the 4 phases into 3 phases, so that (DS) is 0.73 so that it can be concluded that the intersection conditions the signal becomes effective. Meanwhile, the green light time for the north approach is 70 seconds, south is 50 seconds, the east and west approach is 70 seconds