Among the available methods of creating selectable variation, induced mutagenesis has been historically under-utilized in cotton improvement. Dick Auld showed that chemical mutagenesis could be used to enhance fiber length of a medium staple cotton cultivar without sacrificing yield. The goal of this project was to determine if mutagenesis could be used to improve the fiber quality of a germplasm line already considered to be at the upper-limits of fiber length. Seed of TAM 94 L-25 were treated with EMS in 2001 and the M2 generation was produced at Lubbock, Texas in 2002. More than 1200 M3 plants were grown at College Station, Texas in 2004, harvested individually, and HVI fiber properties determined. The top and bottom 1 percent for UHML, strength, and elongation were selected and the seeds of these individuals planted as an M4 progeny row nursery in 2005. Approximately ten individual plants per progeny row were harvested for re-evaluation of fiber parameters. From the approximately 1600 individual TAM 94L-25 M4 plants harvested in 2005, 61 were selected and subsequently treated as pure lines. Agronomic performance trials were conducted on 61 of those TAM 94L-25 M lines along with the M0 check and two commercial cultivar checks, Fiber Max 832 and Phytogen 355, in 2008 and 2009 in College Station and Weslaco, Texas. Within-boll yield components were examined for 13 representative mutant lines and the three checks. TAM 94L-25 averaged 751 kg lint ha^-1, 31.1 mm UHML, 303 kN m kg^-1 fiber bundle strength, and 6.0 percent elongation. The 61 mutant lines yielded from 366 to 932 kg lint ha^-1, exhibited UHML from 24.3 to 34.9 mm, fiber bundle strengths of 261 to 333 kN m kg^-1, and elongations from 5.4 to 8.1 percent. Seed surface area of the TAM 94L-25 M-lines was between 99 and 124 mm^2, and fibers per unit seed surface area from 123 to 168 fibers mm^-2. The M0 parent, TAM 94L-25 averaged 125 mm^2 seed-1, and 128 fibers mm^-2. The data presented herein demonstrate that EMS-induced mutagenesis was successful in creating TAM 94L-25 M-lines with superior fiber and yield traits to that of the non-mutated, high fiber quality parent, TAM 94L-25.