Parasitic angiosperms directly attach to host plants using specialized organs known as haustoria, which function as physiological bridges to extract nutrients and water from their hosts. Cuscuta species (dodders) are common and agriculturally destructive flowering stem parasitic plants. Many Cuscuta species are significant agricultural pests leading to crop yield upon infestation.Because of the intimate physiological connection between host plants and parasites, most traditional herbicides and control methods have not been effective or are too costly. We used transcriptomics to identify genes upregulated in Cuscuta upon attachment to host, as well as host genes upregulated in response to infestations. Gene expression was manipulated in the host and the parasite to study the impact on parasite attachment. The results of this study, and methods developed by us, may help develop a resistant system in crops infested with other parasitic species like broomrape.