Data from field research conducted in 1996 and 1997 on a Loring silt loam (fine-silty, mixed, active, thermic, Oxyaquic Fragiudalf) were used for economic evaluation of plant growth regulators and fertilizer additives in cotton (Gossypium hirsutum L.) production. Disk-till and no-till treatments applied in-furrow at planting included ammonium polyphosphate (11-16-0) applied at 2.33 L ha-1; 11-16-0 + Asset applied at 2.33 and 0.15 L ha-1, respectively; Asset RTU applied at 1.17, 1.75, and 2.33 L ha-1; PGR-IV applied at 0.07 L ha-1 followed by two foliar applications of 0.29 L ha-1 each; and a check. For the disk-till system,Asset RTU applied at 2.33 L ha-1 produced higher yield and net-revenue means than did all other treatments except Asset RTU applied at 1.75 L ha-1. Asset RTU applied at 2.33 L ha-1 produced higher yield and net-revenue means than PGR-IV and the check for the no-till system. The PGR-IV treatment would not be economically preferred by producers for either tillage system due to higher material costs without adequate increases in yields and net-revenues. All but one of the break-even cotton lint prices for comparisons between treatments were more than two standard deviations from the mean cotton lint price of $1.38 kg-1, which suggests that a producer’s decision about which material to apply is not sensitive to fluctuations in cotton lint price. Furthermore, break-even cost differences between any two treatments were many times greater than budgeted cost differences, suggesting that economic choices among the treatments are not sensitive to reasonably expected future cost changes. These results will help cotton producers make decisions about starter fertilizers, fertilizer additives, and plant growth regulators for their tillage systems.