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Theoretical Background: Rice is one of the most important crops and contributes significantly to human nutrition, meeting the requirements for high-energy foods. A highly competitive weed, a relative of rice, red rice (Oryza sativa), has evolved into the most important crop weed. Red rice is a significant and ongoing threat to the long-term sustainability of the rice industry. Clearfield and Provisia rice varieties are the only technologies available for selective (herbicide use) management of rice. Aim: The aim of the present research was to investigate the sensitivity of different biotypes of red rice and late watergrass (Echinochloa phyllopogon) to the herbicide cycloxydim, which is selective in Provisia rice varieties and was recently introduced in rice cultivation in Greece. Method: A greenhouse experiment was conducted in which the 20 red rice biotypes and the 2 late watergrass biotypes were established in pots with 3 pots (replicates) for each treatment. The number of shoots and the fresh weight of the weeds were evaluated 4 weeks after the application of the herbicides (cycloxydim from Provisia technology and imazamox from Clear Field technology). Results: The two late watergrass biotypes were susceptible to the herbicides cycloxydim, imazamox and profoxydim, which caused excellent reduction (>90%) in weed shoot number and fresh weight. The herbicide imazamox did not satisfactorily reduce shoot number and fresh weight of most red rice biotypes. In contrast, application of the recommended dose of cycloxydim caused a satisfactory (>85%) reduction in shoot number and fresh weight of red rice biotypes. In conclusion, the Provisia technology will contribute to the management of red rice in fields where red rice has developed resistance to imazamox.