Limited water supplies for irrigation on the Texas High Plains frequently result in sugarbeets (Beta vulgaris L.) being grown with irrigation amounts less than that re­ quired to fully satisfy evapotranspiration (En. This re­ search was conducted to determine the influence of sea­ sonal irrigation amount on sugarbeet yield, sucrose, water use efficiency, and purity factors . Seasonal irriga­ tion treatments designated as none, limited, and adequate received an average of 0, 10.7, and 20.3 inches respectively, of irrigation between 10 June and 10 Sep­ tember during seven years of study. Fertilizer N was adjusted, when possible, for the anticipated yield level of each irrigation treatment. Weather conditions were generally favorable so yields were high for all treatments. Total ET averaged 28.3, 38.5, and 46.7 inches and root yield averaged 18.6, 27.9, and 35.5 tons/A for none, li­ mited, and adequate irrigation, respectively. Limited sea­ sonal irrigation was slightly more efficient in increasing sucrose production per acre-inch of seasonally applied water than adequate seasonal irrigation. However, in terms of ET, efficiency of sugar production improved slightly as ET increased. Root yield and sugar production were highly dependent on ET. Difference& in ET explained 90% of the variability for yield over the 7-year period. Sucrose percentage was increased by low seasonal irrigation one year in seven. On the other hand, greater seasonal irrigation consistently reduced total impurities and sucrose loss to molasses which resulted in a higher percentage of recoverable sucrose. The drier irrigation treatments had greater amino-N in sugarbeet roots at har­ vest even though less fertilizer N was applied to the drier treatments. Thus, sugarbeets can be efficiently grown with a wide range of seasonally applied irrigation on the Texas High Plains; however, impurities in the roots will increase as seasonal irrigation is reduced.