The city of Fustat which is located in Cairo, Egypt, was the first Islamic city in Africa. The site underwent excavation works that revealed some city and buildings. Excavations stopped in 1975, and from that time the site started to deteriorate. The most important deterioration factors were the urban expansion and the rising of groundwater level, besides lacking any regular restoration or evaluation works. The study aims to monitor the state of preservation of the Fustat excavations site and track the stages of its deterioration during a specific period (23 years). This helps in monitoring the rate of deterioration during that period, thus predicting the condition of the site during a similar future period of time or more. To achieve these aims, the following methodology was suggested: a. monitoring the current deterioration phenomena and its causes, b. determining the state of archaeological building materials by taking small representative samples from the fired bricks and mortar, and c. standard samples of fired bricks and mortar were used for the comparison with the results of the current samples in order to determine the status of preservation of the archaeological building materials at the site.