Traditionally, commercially grown potatoes are hilled in the production cycle between emergence and closure of the canopy. Hilling is usually accomplished with disks, sweep shovels, or similar tools that lift soil from between rows and deposit it beside and on top of the row. Reasons for hilling may include: improved weed control, improved drainage, minimization of greening of tubers, and raising of soil temperatures. Proper management of each of these factors may result in an increase in quality and quantity of tuber yield. Negative aspects of hilling have also been noted. Saffigna et al. (1976) reported that water distribution was uneven under potato hills, resulting in uneven availability of water to plants and increased loss of fertilizer due to leaching. Hilling operations may also damage potato plants, and significant reductions in yield are known to result from hilling and other types of cultivation (Nelson and Giles, 1986). Many commercial growers wait until vines are 12 or more inches tall before hilling. This scheduling is preferred because at this time the danger of covering plants is minimal. However, the vines of larger plants may sustain greater damage from hilling than smaller plants. Also, the possibility of damaging roots and stolons increases as the plants increase in size, so there may be advantages to hilling when plants are younger and smaller. Four different treatments including variations in time of hilling and height of hill were compared with no-hilling on four varieties of potato in the 1988 and 1989 growing seasons. This report contains a preliminary summary of data collected from these studies.