Honeybees (Apis mellifera) depend on floral nectar for carbohydrates and on a diversity of floral pollen as sources of proteins. It is remarkable that they only possess ten gustatory receptors (Grs) for carefully evaluating the diverse floral resources they encounter. The fruit fly, for example, has a broad set of 69 genes for taste perception and the mosquito even has 75 genes. So far, three honeybee taste receptors have been characterized in a Xenopus cell system. For the first time we characterized honeybee taste receptors in vivo in adult honeybees employing the novel CRISPR/Cas9 technique. Knocking out individual taste receptors we can show that AmGr1 double mutants showed a reduced response to sucrose and glucose, but not fructose. AmGr3 mutants are insensitive to fructose, but not sucrose, confirming that this receptor is a specialised fructose receptor. AmGr2 mutants did not show any differences compared to wild type bees, confirming that this receptor is a co-receptor only. Our results demonstrate that CRISPR/Cas9 is a strong molecular tool for honeybee research, allowing functional analysis of receptors in live bees combined with behavioural studies.