Field experiments were conducted in 2005 at the Powell Research and Extension Center, Wyoming to determine the influence of various densities and durations of Venice mallow (Hibiscus trionum L.) and wild buckwheat (Polygonum convolvulus L.) interference in sugarbeet (Beta vulgaris L.). Season long competition by Venice mallow densities of 2, 4, 6, 8, and 10 plants per m of sugarbeet row decreased sugarbeet root yield by 8, 14, 15, 29 and 29% respectively.  Linear regression analysis showed a weak correlation (R² = 0.69) between Venice mallow density and sugarbeet root yield reduction. However, there were no significant differences in the sucrose content for the various Venice mallow densities. There were no significant differences in root yield and sucrose content with 2, 4, 6, 8, 10, and 12 weeks of Venice mallow competition after sugarbeet emergence. Sugarbeet root yields and sucrose content were not influenced by wild buckwheat densities of 2, 4, 6, 8, and 10 plants per m of row. Similarly, there were no significant differences in root yield and sucrose content with 2, 4, 6, 8, 10, and 12 weeks of wild buckwheat competition after sugarbeet emergence.