Lepidopteran stemborers are among the most important field insect pests of cereal crops in sub-Saharan Africa. With the exception of Chilo partellus, all other borer pests are indigenous to Africa and are assumed to have co-evolved with some native grasses and sedges. Understanding the interactions between pest species and their cultivated and native hosts are required to develop sustainable management strategies. In addition to pest species, natural habitats support diverse range of species (non-pests and their associated natural enemies) some of which are unknown to science. Although the stemborer—host plant interactions have been well described for eastern and southern Africa, knowledge regarding distribution and diversity of stem borer species and their host plants in western and Central Africa is limited. Existing knowledge of the stemborer species diversity of these regions indicate a lower specific and generic diversity compared to eastern and southern Africa. There is need to undertake extensive surveys in Central Africa, particularly in southwestern Cameroon, an area considered as principal centre of diversity and endemism in Africa. This paper provides results of the survey undertaken to establish stemborer species diversity and geographical distribution in Cameroon. A total of 32 stemborer species were identified from the 22 plant species found infested. This information is necessary for future studies on the biogeography and evolution of the noctuid stemborers.