Economic benefits from irrigating peanuts in the humid Southeast are often marginal or negative because proper consideration must be given to the complex relationships of plant, soil, pest and weather. Computer programs EXNUT and MOISNUT were developed to consider these complex relationships and to recommend timely irrigation of peanuts. A 3-yr study was conducted to evaluate the feasibility of using these computer programs for scheduling peanut irrigation on sandy and medium textured soils in Georgia. During 1994-1996, irrigation was applied two to nine times as recommended by these two computer programs. Net returns to irrigation were $490/ha higher for irrigated plots with these two programs than for nonirrigated plots. Serious compaction problems negated irrigation benefits in 1994 on the medium textured soil, and poor fertility and high disease pressure on the sandy soil negated irrigation benefits in 1995. Without these problems, the average benefit was $920/ha. During 1996, the irrigation benefits from using EXNUT and MOISNUT programs and the fungicide Folicur averaged $1098/ha and $1011/ha for sandy and medium textured soils, respectively. On the average, market grade of the irrigated peanuts were higher than for the nonirrigated peanuts. No aflatoxin (< 1 ppb) was found in edible grade peanuts where these computer programs were used to manage irrigation. Based upon this study and previous research, the EXNUT and MOISNUT computer programs are very useful for scheduling irrigation on peanuts. Proper use of these computer programs should minimize the negative aspects of irrigation for fields with high disease pressure and fields that produce plants with shallow root systems.