The main strategy of interrupting Trypanossoma cruzi transmission is to control the vector populations. Studies of new agents with activity against these vectors have a priority interest. This study evaluated the insecticidal activity of the essential oil of Myrciaria floribunda against nymphs of R. prolixus. M. floribunda was collected in Jurubatiba Sandbank (southeastern Brazil). Leaves were extracted by hydrodistillation and the essential oil analyzed by mass spectrometry and flame ionization gas chromatography. The pure essential oil at various dilutions or purified 1,8-cineole was topically applied to R. prolixus. Sesquiterpenes were the main group detected followed by monoterpenes. M. floribunda essential oil, but not 1,8-cineole, significantly increased mortality and disrupted metamorphosis. Overaged nymphs and juvenoid-like insects were also observed. Our data indicate the special metabolites in the essential oil of M. floribunda as promising candidates for studying insecticidal activity and for use as environmentally friendly control compounds to Chagas disease vectors.