Water scarcity in U.S. peanut production is leading to an emphasis on developing production practices which maximize crop water-use efficiency. In a peanut production setting, water scarcity is dealt with by using a variety of management practices including irrigation rates and methods as well as tillage practices known to increase soil moisture during drought. To investigate the efficacy of such production practices on seasonal water-use efficiency and other leaf characteristics in peanut, field trials were conducted in 2002, 2003, and 2004 in which irrigation rate and tillage practice were tested. The field consisted of a factorial combination of four irrigation rates (100%, 66%, 33%, and 0% crop water use replacement) and two tillage treatments (conventional and strip tillage). Within each irrigation and tillage treatment, peanut tissue isotope composition (δ¹³C, δ¹⁵N), SPAD chlorophyll content, and specific leaf area were measured. Effects on δ¹³C (a surrogate for seasonal water-use efficiency in peanut) were significant for irrigation rate, with greater δ¹³C in irrigated treatments than in dryland. The only significant effect of tillage was on δ¹⁵N that showed lower contents in the strip tillage system. SPAD chlorophyll content was significantly lower in 0% and 33% irrigation levels than in the fully irrigated treatment. When combined with an economic analysis of irrigation costs, this data will aid in identifying the irrigation and tillage practices that maximize water-use efficiency in U.S. peanut production.