The CSIRO Advanced Lines Trial(ALT) has been run cooperatively by CSIRO and DPIQ for 26 years and is used as the last stage in our breeding line evaluation. Early generation testing following single plant selection involves unreplicated progeny rows at the Australian Cotton Research institute, further progeny row tests and multiple row replicated trials at a limited number of farm sites. At each stage, lines with poor seedling vigour, disease susceptibility, poor fibre quality or low yield are removed from further testing. The ALT involves 13 irrigated sites in all major cotton growing regions in Australia. Management is normal commercial practice including full insect control Entries in the ALT include promising breeding lines and commercial standards. Ingard varieties are included in the ALT even though the trials are conventionality sprayed. Their performance indicates yield potential relative to their conventional counterparts and also gives an indication of the insect pressure experienced. Plots consist of three or four rows from 10 to 14 metres long and four replications are used. The centre rows of all plots are harvested with a modified picker, the seed cotton weighed and a subsample is taken for ginning at Biloela or Narrabri and fibre quality analysis at Narrabri. The most promising lines are retained in the scheme and also seed increased. In this way, by the time good performance is confirmed, sufficient seed is available for large scale testing and final seed increase for cornmercial use.