This small and almost intact temple was one of the first discoveries during the excavation of Pompeii in 1764. Its role as a Hellenized Egyptian temple in a Roman colony was fully confirmed with an inscription detailed by Francisco la Vega on July 20, 1765. Original paintings and sculptures can be seen at the Museo Archaeologico in Naples; the site itself remains on the Via del Tempio di Iside. In the aftermath of the temple's discovery many well-known artists and illustrators swarmed to the site.

The Temple of Isis was a significant aspect of life in Rome. It was in a central location near the Forum, theaters, wrestling school, and temples honoring gods, Asclepius and Neptune.

circa 80-79 BCE

The temple, situated in a central position and looking eastward, was constructed on a high podium that was meant to be big enoughto contain the whole Isiac family; in the cella, which is wider than its length, the statues of Isis and Osiris; outside the cella, in two niches to either side of the pronao, the statues of Harpocrates and anubis, to whom the two side altars corresponding to the same niches were dedicated. On the rear wall (inspect) of the cella, inside a niche, a statue of Baccus with a panther was presented. On the opposite side is a votive pit in which the ceremonial remains and offerings were preserved.

It features a vaulted roof, drawing attention to the top of the building. This style of roofing was a Roman stylistic influence, yet was becoming phased out by the time the temple was built. Weber, who excavated the temple, speculated that the Temple of Isis was built according to the Corinthian order. The architecture of the Temple of Isis is a fusion of Greek, Roman, and Egyptian features, incorporating Egyptian statues in the design. The mixture of Eastern stylistic influences with Hellenistic paid tribute to Isis' Egyptian roots, while still keeping the imagery domestic. In comparison to authentic Egyptian temples, the Temple of Isis was very much in line with the Roman architectural style.

The Temple of Isis sits on a platform which is elevated off the ground, and entered in by way of stairs. The temple is designed based on a north-east and south-west plan. The Temple of Isis had two sections: an outer space surrounded by columns, called the pronaos; and the inner area - naos - which housed the statues of Isis and Osiris. Both areas of the temple were entered and exited through ornate niches. Though it is not a large structure, both the interior and exterior of the monument are elaborately decorated. Inside the inner chapel was a holding space for a statue of Isis. Further into the temple are altars and recesses in the walls; outside of the temple was a crypt used for initiating members into the cult. Upon analysis of the remains of the temple, it is known that it was painted with a red and white color scheme throughout. The white paint was meant to emulate a stone-like appearance.

Structurally, it was built in the open air area of a peristyle - with columns all around; twenty-nine total.

In a corner of the courtyard or peristyle is the purgatorium (inspect), an open-roof construction entirely decorated with stucco work, used for purification ceremonies. Inside it a series of steps lead to an underground space where a bath and a podium supporting the receptacle in which the sacred water of the Nile was kept were preserved. It was a roofless enclosure in the southeast corner of the courtyard that demarcates a subterranean room with a basin for Nile waters. The water from the Nile functioned as holy water used for rituals. The structure itself resembles a miniature temple with pediments and pilasters at the entrance coated with stucco.

Furthermore, statues of Isis are assumed to line the front of the temple with Roman deities along the long walls.