The two unusual pyramidoid buildings of Argolida region have already been known since the beginning of the century, when the first research was carried out there by German and American archaeologists. The two buildings had almost been forgotten, when recently the Athens Academy, with a scientific team in which the author of this article also participated, carried out a geophysic research around them in order to locate other buildings as well as a test excavation. The excavational research in the pyramid of Ligourio was held in 1993 and revealed buildings of the Late Classic, Hellenistic and Early Christian period (5th-6th century A.D.). The excavation in the pyramid of Hellenikon produced buildings and pottery mainly of the Early Christian years, while a section in contact with the monument produced pottery of the Protohelladic period (first half of the 3rd millenium B.C.). Although the problem of dating the pyramids was not solved with this test excavation, however, on the basis of the data available so far we can support quite effectively certain arguments and reject some other shallow views. As regards the Lygourio pyramid, the previous as well as the recent excavation did not reveal any find earlier than the 5th-4th century B.C., a period which corresponds to the date of the masonry of the building. Of course, Pausanias’ account leads us back to earlier years, may be to the beginning of the Mycenaean era, however, relevant pottery has not been found around the pyramid. In the Hellenikon pyramid the excavation did not produce any indicative pottery, apart from a few sherds dating from the Classic and Hellenistic years. The abundant Protohelladic pottery relates to a settlement of the same date, once existing in this location, and has no connection whatsoever with the pyramid. The older excavation has already proved that the monument stood on Protohelladic constructions, therefore it was built in a later time. Besides, the masonry of the pyramid, similar to that of Ligourio, leads us to the Classic or Late Classic years. A new method for dating the stone, recently applied to the pyramids, indicated a too early dating in the 4th and 3rd millenium B.C., which of course cannot be accepted. The excavational data and our knowledge of the Protohelladic period in the entire Greek area exclude the construction of similar edifices in such early years. As regards the function of the two buildings, it seems that it was different from one period to another. It is very plausible that these edifices were truncated pyramids, originally roofless. They may have been used as sanctuaries or have been erected in order to commemorate some important events; it is also possible that they have practically remained unused.