The church of the Panagia (Virgin Mary) in Kastamonitsa is located inside the cemetery of the village and is dedicated to the Assumption of the Virgin (feast 15 August). The folklorist Georgios Stamatakis considers that it was probably a Catholic monastery, since it is not recorded in any census of temples during the Venetian Era (the monasteries were not listed). It has exterior decorative boards (colored round pots called pinakia) and an elaborate bell tower, while we see several architectural parts from the ancient city Lyttos.
The interior of the temple bears frescoes in poor condition dating back from the 14th century and a wood-carved iconostasis from the mid-19th century by the Makrakis brothers from Mesa Lasithi. The 14th-century frescoes were struck for better adhesion to the plaster, thus destroyed. From the fresco decoration, we can hardly discern the hierarchs at the lower point of the semi-cylindrical arch of the sanctuary and a part of Panagia Platytera (Theotokos facing the viewer directly with open hands). On the west wall there is the Dormition of the Virgin Mary with Michael Archangel above the entrance and the healing saints Anargyri, Kosmas and Damianos to the right of the entrance.