The response of two Acala cotton (Gossypium hirsutum L.) varieties and one Pima (G. barbadense L.) variety to combinations of three rates of subsurface drip irrigation and different periods (growth stages) of deficit irrigation were investigated in the western San Joaquin Valley of California. Water application rates were 60%, 80% or 100% of estimated crop evapotranspiration (ET(c)), with treatments ranging from full-season 60%, 80% or 100% ET(c) applications to progressive reductions in applied water during flowering or boll-development periods. Mid-afternoon leaf water potentials of even the 60% ET(c) treatments generally were higher than -2.0 MPa until late in the season, indicating extensive use of stored soil water. Increases in lint yields as ET(c) exceeded 700 mm were quite small (7% or less). Moderate and more severe deficit irrigation treatments resulted in significant differences in growth (leaf area, height, total dry matter). Petiole NO₃-N, PO₃-P, and K levels were not significantly influenced by subsurface drip irrigation treatments or variety within the Acala varieties, but NO₃-N levels were consistently 10-15% lower in Pima despite identical fertilizer applications. Above-ground plant accumulations of N, P, and K averaged 244, 54, and 209 kg/ha, respectively, and were significantly reduced with increasingly severe deficit irrigation.