The reproductive cycle of the small temperate dendrochirote holothurian Eupentacta chronhjelmi was studied in the intertidal zone of Aoshima Island, in the Seto Inland Sea of Japan, from July 1989 to January 1991. Reproductive status was assessed by the gonadal index method and histological analysis of the largest (tertiary) gonadal tubules. The primary and secondary tubules are cryptic and difficult to find, so no reference to the animal's annual cycle in terms of gametogenesis is made. The gonad wall was thickest in September for females and October for males, when the gonadal index was at its peak the rapid final stages of vitellogenesis in females (and completion of spermatogenesis in males) depleted reserves in the gonad wall, producing gametes that were spawned in October to December. When gametes were spawned in December the gonadal index and gonad wall thickness decreased. We suggest that the gonadal index reflects gonadal growth by oocyte production and an increase in gonad wall thickness. In the laboratory, spawning occurred from midnight to 04:00, at ambient seawater temperature (12 °C). Individuals elevated their anterior, oral end, waved their tentacles, and released gametes for about an hour. Based on its large egg size (300 ± 5 μm (mean ± SE) diameter) and low fecundity (1500 ± 10 ripe oocytes per individual), we infer lecithotropic development with an abbreviated larval stage.