In planning the mosque, the architects incorporated a number of Roman columns with choice capitals. Some of the columns were already in the Gothic structure; others were sent from various regions of Iberia as presents from the governors of provinces. Ivory, jasper, porphyry, gold, silver, copper, and brass were used in the decorations. Marvellous mosaics and azulejos were designed. Panels of scented woods were fastened with nails of pure gold, and the red marble columns were said to be the work of God. The primitive part of the building, erected under the direction of Abd al-Rahman I., was that which borders the Court of Oranges. Later, the immense temple embodied all the styles of Morisco architecture into one composition.

The Great Mosque of Córdoba held a place of importance amongst the Islamic community of al-Andalus for three centuries. In Córdoba, the capital, the Mosque was seen as the heart and central focus of the city.^[28] Muhammad Iqbal described its hypostyle hall as having “countless pillars like rows of palm trees in the oases of Syria”.To the people of al-Andalus “the beauty of the mosque was so dazzling that it defied any description.”

The main hall of the mosque was used for a variety of purposes. It served as a central Prayer hall for personal devotion, the five daily Muslim prayers and the special Friday prayers. It also would have served as a hall for teaching and for Sharia law cases during the rule of Abd al-Rahman and his successors.

The Great Mosque of Córdoba exhibited features and an architectural appearance similar to the Great Mosque of Damascus, which may have been used as a model.

The building is most notable for its arcaded hypostyle hall, with 856 columns of jasper, onyx, marble, granite and porphyry. These were made from pieces of the Roman temple that had occupied the site previously, as well as other Roman buildings, such as the Mérida amphitheatre. The double arches were an innovation, permitting higher ceilings than would otherwise be possible with relatively low columns. The double arches consist of a lower horseshoe arch and an upper semi-circular arch. The famous alternating red and white voussoirs of the arches were inspired by those in the Dome of the Rock and also resemble those of the Aachen Cathedral, which were built almost at the same time. Horseshoe arches were known in the Iberian Peninsula since late Antiquity, as can be seen on the 3rd-century “Estela de los Flavios”, now in the archaeological museum of León. A centrally located honeycombed dome has blue tiles decorated with stars.

The edifice also has a richly gilded prayer niche or mihrab. The mihrab is a masterpiece of architectural art, with geometric and flowing designs of plants. Other prominent features were an open court (sahn) surrounded by arcades, screens of wood, minarets, colourful mosaics, and windows of coloured glass. The walls of the mosque had Quranic inscriptions written on them. As many adherents of Islam reject sculptural or pictorial representations of people or of God within religious contexts, all decoration of the cathedral is accomplished through tile work, calligraphy and architectural forms. Arrazi, an Arab writer, speaks of the valuable wine-coloured marble, obtained from the mountains of the district, which was much used in embellishing the naves of the mosque.