Abstract The essential oils isolated separately from fresh leaves and from inflorescences of Hemizygia welwitschii (Rolfe) M. Ashby collected in the Adamaoua Province of Cameroon were obtained by hydrodistillation and analyzed by GC and GC/MS. Forty three compounds representing 89.1% and 91% of the oils were identified. The aliphatic compounds were the most abundant (51.1% and 51.8%) in both samples among which (Z)-3-dodecenoic acid predominated (26.1% and 46.1%). In the leaf oil, 1-octen-3-ol was the other major component (14.1%) whereas it was found in minor amounts in the oil obtained from flowers. In the terpenoid series, sesquiterpene hydrocarbons were present in equal amounts (18.6% and 17.4%), with about 5% of (E)-Î²-farnesene.