This study aims to determine the proper planting period for the planting of cassava in Kirik variety in Gunungkidul Regency. This research was conducted using a field experiment method with a single factor experimental design that was arranged in a Complete Randomized Block Design (RAKL). The test that was tested was planting time, consisting of 3 treatments namely, Planting the 1st month in September, Planting the 2nd month in October and Planting the 3rd month in November. Each treatment carried out 3 replications so that there were 9 treatment units. Each treatment unit consists of 3 sample plants for observation. The results showed that the cassava planting time of Kirik variety in September gave the highest yield (14.633 tons / ha) with a 5-month old yam harvest time.