The prayer hall of mosques is an open space without furniture as the performance of the salat (prayer) requires space for movement. As the praying area must always be clean, one's footwear must be removed before entering the prayer hall and its floor is usually covered with carpeting or matting.

The focus of the prayer hall is the qiblah wall, which is the most decorated wall in the mosque, with the mihrab (niche) - at its centre. The qiblah wall orientates the prayers of Muslims from all parts of the world towards the Holy Ka'bah in Mecca.

The mihrab (niche) and the qiblah wall are essential elements in all mosques except the Holy Mosque in Mecca (as the Ka'bah is within the mosque).

The stepped pulpit placed next to the mihrab is the minbar, a feature that has existed since the time of the Prophet. The use of the minbar became established after a caliph named Mu'awiya in 750 CE ordered it to be included in all mosques of Egypt. The Friday khutbah (sermon) is read from the minbar and since early times in Islam, the content of the khutbah could contain political announcements.

Wuduk (ablutions) must be done before Muslims can perform the salat. This act of washing the exposed parts of the body with water has to be accompanied by internal purification, for salat involves total concentration of body motions, mind, and presence of heart. The ablution area is usually found within the mosque compound.