The availability of Roundup Ready cotton has been an important factor influencing the revival of ultra-narrow-row cotton (UNRC) as an alternative cotton production system. Farmers are concerned about the high costs of Roundup Ready technology fees associated with the large plant population densities (PPD) recommended for UNRC production. This study evaluated the effects on UNRC net revenues of four different Roundup Ready cotton technology fee regimes used since 1996 by Monsanto, the technology license holder. Results indicate that the yield gains with increased PPD for UNRC were very small. As a consequence, there may be an incentive for farmers to use a much lower PPD to reduce seed and technology costs by more than the loss of yield with the lower PPD. How far PPD was reduced depended on whether or not the Roundup Ready technology fee was tied to the seeding rate. Under the 1996-97 policy, the per acre technology fee was the same regardless of the target PPD used to determine the seeding rate at planting. As a consequence, the choice of target UNRC PPD was not influenced by the technology fee. Nevertheless, the profit maximizing PPD was well below the 19.8 to 49.4 plants m^-2 typically recommended for UNRC. The Roundup Ready technology fee per acre was higher under the 1998-2003 UNRC exception policy. Potential differences in the plant survival ratio assumed by Monsanto and the plant survival ratio assumed by farmers in determining a target PPD were the primary factors influencing the higher technology fee cost. Because technology fee cost was tied to the seeding rate, the profit maximizing PPD was lower than under the 1996-97 policy. Results indicate that UNRC technology fee costs were the largest under the 2004-05 fee cap policy. Farmers may be able to save on seed cost but not the technology fee by reducing the target PPD under the fee cap policy. This was because the maximum fee of $28/acre under the fee cap policy was in effect for all of the feasible PPDs for UNRC.