|Abstract||Using ground speeds and extractor fan speeds recommended by Harvesting Best Practice (HBP) will minimise cane loss and stool damage. While these benefits provide an incentive for growers to request contractors use HBP settings, little research based on trial data has examined the full impact on harvesting costs. Given that reduced ground speeds increase harvesting time, it is expected harvesting contractors would incur higher labour, fuel and machinery costs per tonne. To incentivise the move to HBP, additional compensation would need to be paid to harvesting contractors by growers. It is anticipated that providing growers and contractors with information about the harvesting cost implications from implementing HBP would enhance adoption. The difference in harvesting costs between conventional (standard) harvesting practice and HBP (recommended) are evaluated at nine harvesting-trial sites undertaken across Queensland in 2017 by Sugar Research Australia. The analysis draws upon the production and operational information collected during the trials along with detailed information collected from each of the nine harvesting operations. A customised economic spreadsheet was developed to model the difference in harvesting costs between standard practice and recommended settings. Harvesting costs per tonne were generally found to increase when using recommended settings, with the exception of trials that attained large reductions in cane losses due to the change in practice. The results showed that changing to recommended settings increased harvesting costs by between $11 and $101/ha. Changes per tonne showed far more variability at –67 c/t (saving) to 96 c/t (increase), where some cases showed cost increases offset by yield improvements. Moreover, harvesting costs varied among harvesting contractors due to differences in machinery-management strategies and labour-payment terms. Sensitivity analyses were also undertaken to investigate the response of harvesting costs to different scenarios.