Abstract The volatiles of Ageratum conyzoides collected at the municipality of Santarém Novo (Samples A, B and C), and Belém (Sample D), State of Pará (North of Brazil), were obtained by hydrodistillation and analyzed by GC-FID and GC-MS. The inflorescence, leaf, stem and root oils of the Sample A were dominated by precocene I (inflorescence: 55.5%, leaf: 69.6%, stem: 71.6%, root: 67.4%), followed by β-caryophyllene (inflorescence: 19.4%, leaf: 14.4%, stem: 12.8%, root: 15.3%). The oils from the whole plant of the Samples B, C and D were rich in α-pinene (Sample B = 23.4%, Sample C = 14.4% and Sample D = 12.0%), and germacrene D (Sample B = 13.2%, Sample C = 15.3% and Sample D = 16.1%). The obtained data showed the occurrence at least two chemotypes of A. conyzoides in Pará: the type rich in precocene I, comparable to the oils from Cameroon, Ghana and Burkina Faso, and Southeast of Brazil, and the type rich in α-pinene/germacrene D.