Motozenkō-ji Temple, Buddhist temple in Iida, Japan.

Motozenkō-ji is a Tendai Buddhist temple in the Zakkōji district of Iida, Nagano Prefecture. Its main hall has a steeply pitched grey-tiled gable roof; below it, a dark wooden facade carries a gold-lettered plaque, and a white awning with black tree motifs and the characters 宝物拝観 hangs across the front. The grounds also hold a treasure hall and a Peace Hall.

The temple was founded in 602 during the reign of Empress Suiko and originally housed the principal statue now enshrined at Zenkōji in Nagano. This connection to early Buddhist times makes it one of the oldest religious sites in the Shinano region.

The ritual is called okaidan-meguri: visitors keep their shoes on and follow a handrail through darkness from the outer hall of the main hall, modelled on passing through the Buddha's womb. At the end they touch a lock directly beneath the principal image, said to bring rebirth in paradise and good fortune. The temple also keeps the story that the Buddha promised to return to Iida for fifteen days each month, hence the saying that worshipping at Zenkōji and Motozenkō-ji both is required.

The temple is a five-minute walk from Motozenkōji Station on the JR Iida Line. Visitors enter the main hall for the Kaidan-meguri wearing their shoes, following a handrail through the dark to touch the lock beneath the principal image. The treasure hall displays the Zakoji mortar, a Nirvana statue and a Fujiwara-period Aizen Myōō statue.

The temple grounds hold a 350-year-old weeping cherry tree designated as a cultural property of Nagano Prefecture. The tree blooms in spring and draws visitors who come to admire its drooping branches and dense cloud of pink blossoms.