A phytochemical investigation of a medicinal plant Artemisia atrovirens was carried out, resulting in the characterization of a novel bis-nor seco- guaianolide, seco -atrovirenolide A (1), a new 1,10- seco -guaianolide derivative, seco -atrovirenoic acid A (2), and a new artifact 10-methanoyloxy- seco -atrovirenoic acid A (3), together with eight known guaianolide and seco -guaianolide derivatives (4 – 11). The structures of new compounds were fully established by extensive analysis of MS, 1D and 2D NMR spectroscopic data. The absolute configurations of the isolated compounds were confirmed by TDDFT ECD calculation, Mosher's method, and X-ray crystal diffraction experiment. All the compounds were tested in vitro for their cytotoxicity against HL-60 and A549 cell lines. Some of them showed moderate inhibitory activity against HL-60 cell lines with IC 50 values ranging from 5.99 to 11.74 μM. [Display omitted] • Three new 1,10- seco -guaianolide derivatives (1 – 3) were isolated from the whole plant of Artemisia atrovirens. • Compound 1 featured a rare bis-nor seco- guaianolide skeleton. • The absolute configurations of 1 – 6 and 9 were determined by TDDFT calculated electronic circular dichroism (ECD), Mosher's method, and X-ray diffraction. • Compounds 5 , 6 , 9 , 10 , and 11 exhibited moderate cytotoxicity against HL-60 and A549 cell lines. [ABSTRACT FROM AUTHOR]