The timely availability of water for cotton production on the Texas High Plains (THP) is a limiting factor, particularly as well capacities in the region decline. Approximately 40 % of the total planted land area is irrigated and approximately 150,000 acres are irrigated by sub-surface drip (SDI). Cotton varieties used for SDI range from conventional to modern transgenics and new varieties are becoming available each year. Since little is known concerning the interaction of SDI technology and seasonal plant development, the objective of this study was to determine the impact of SDI on water use, root and shoot development and lint yield of two cotton cultivars known to have different rooting characteristics in the THP. Four irrigation levels (0.1, 0.2 and 0.3 in/day and dryland) were established using the BIOTIC system for SDI irrigation management. Genetic variability for water use, rooting patterns and lint yield were evaluated.