Abstract: Background and Objective: Pesticidal plants have become increasingly popular among small scale farmers in Kenya. Little is known about the efficacy of the non-volatile bioactive compounds of this species. There exist gaps such as the chemical compounds responsible for pest repellency and the right concentration of the botanical extracts. This study, therefore, determined the non-volatile bioactive compounds and evaluated the efficacy of three concentrations of L. javanica complex in control of aphids of Vigna unguiculata. Materials and Methods: Crushed powder of L. javanica leaves which were collected from different localities were used in the preparation of crude extracts, which were then screened for the presence of the bioactive compounds. Three prepared concentrations of 10, 5 and 1% were sprayed on cowpea plants planted on four blocks which had been replicated four times. Cowpea aphids were enumerated according to the categorical indices prior to and after spraying. Synthetic pesticide atom (Osho) and water plus soap were used as positive and negative controls, respectively. Results: Lippia javanica was found to be rich in a variety of non-volatile compounds namely: phenols, flavonoids, tannins, alkaloids, cardiac glycosides and terpenoids that perhaps exhibit pesticidal effects on cowpea aphids. However, phenolic glycosides, resins and polyuronides were absent. Application of the extracts irrespective of concentrations significantly suppressed aphid population at p<0.05. It was notable that aphid suppression increased with increasing concentration. Consequently, the mixture of L. javanica extracts at 10% outperformed 1 and 5% extract concentration. In addition, the 10% extract concentration favorably competed with the synthetic insecticide (Atom, Osho Syngenta). Conclusion: The findings from this study showed that Lippia javanica possessed a wide range of phytochemical compounds; also, the 10% botanical extract was found to be comparable to the synthetic pesticide already in use for control of cowpea aphids.