An experiment was conducted at Narrabri Agricultural Research Station during the 1991-92 season to investigate the response of a range of currently available cotton varieties to irrigation and nitrogen treatments. This experiment, along with the date of planting experiments described by Tony Wells elsewhere in the conference proceedings, forms part of a long-term program to study the agronomic requirements of new cotton varieties. These experiments also provide data for development of crop simulation models including the Hydrologic program. This paper describes the yield and fibre quality results from the experiment and discusses the implications for inigation and fertiliser management of different varieties. Some recommendations also apply to dry land cotton production.