Machine availability estimations from research performed before the following season are needed to decide on the required machinery size necessary for timely operation. Additionally, estimations on machinery availability will provide useful data for making mathematically proven assumptions regarding the repair maintenance and timeliness costs. Machine reliability or operational availability analyses must be carried out, especially for combine drills and combine harvesters, which are relatively more sensitive to timeliness. In the literature, there is rare study on operational availability on combine drills. In this study, failure rates, which are a direct indication of machine operational availability, were evaluated from the farm records of cereal combine drills used in Adana, which is located in Cukurova, one of the major agricultural regions in southern Turkey. These records for combine drills of different ages and with different annual use hours were collected during three subsequent years. Moreover, different repair and maintenance policies in farms under examination were considered. As a result, it was found that different accumulated use hours and repair-maintenance policies have slightly affected failure rates. According to the data, the combine drills included in this study are commonly in a randomized breakdown period within their useful life.