This masjid is named after the name of the Arab conqueror of Sindh, Muhammad Bin Qasim. It was built during the Mughal period. Situated on a ridge opposite Pir Patho, it is not dated, but its style dates to the late 17th century. Actually there are two mosques in a spacious courtyard measuring 180 feet east to west and 162 feet north to south. One of the two mosques is centrally situated, while the southern mosque was added later.
The eastern facade suggests to the casual visitor that both mosques were built at the same time, but their architectural features are different. The facade of the (older) northern mosque has three arched entrances, the central one larger than the other two, and opening under a higher arch. On either side of the central arch is a small arched panel, and on the right side there are two additional panels, one atop the other.
The southern masjid also has three arched openings, each within a rectangular frame. There are no other panels on this face. The three domes of the southern mosque have a clear octagonal drum. The internal arrangement of the two mosques resembles the Khizri Mosque in Thatta, with three bays, the largest in the centre. The phase of transition in the northern mosque is made up by squinches, and in the southern mosque by pendentives. The mihrab of the earlier mosque has arched panels, while that of the later mosque is simple.
These two mosques are joined together. At the point of junction, a staircase on the east leads to the roof. The mihrabs project from the back of the western wall. On one side of the courtyard there is an arched entrance of a later period. At the northeastern corner there is a round, tapering tower built in brick and plaster. Stairs ascend from within to the first floor, and thereafter from the outside up to the second storey. At the base, the tower has a plastered collar. Similarly, the second storey has a plastered parapet, below which there is a ring of dentil decoration. On the top there is a conical canopy crowned by a simple finial. There is an arched entrance, approachable from inside the mosque enclosure. Right above the entrance there was a wooden balcony supported on wooden brackets. Only one bracket is now preserved. It shows double pendants on its lower part. Its sides are decorated with a carved scroll and string course motif.
There are other light and air windows in the second storey. An arched opening is provided to go to the balcony from the first storey. The balcony faces the mosque and it is probable that this was used for the azan (call to prayer). However, the placement of the tower right at the edge of the ridge overlooking the settlement suggests that the so-called Muhammad Bin Qasim’s Minar may also have been used as a watch tower. It is 50 feet high and 72 feet in circumference at the base. In style, it is similar to Mir Masum’s Tower in Sukkur, which was commenced in 1594 and completed in 1618.