© 2018, Turkish Chemical Society. All rights reserved.Two samples of Tanacetum praeteritum (Horwood) Heywood subsp. praeteritum (Horwood) were collected in flowering period and subjected separately to hydrodistillation to yield the essential oils (A and B). The oils were investigated for chemical composition with GC-FID and GC/MS techniques and evaluated against acetylcholinesterase and α-amylase enzymes and free radicals (DPPH• and ABTS•+) using microtiter plate assays. Both oils were characterized with high abundance of oxygenated monoterpenes. The oils were distinguished by the main constituents, namely, camphor (37.6%), 1,8-cineole (19.5%) and terpinen-4-ol (9.3%) were found as the major constituents in the oil A, while α-thujone (79.4%) and β-thujone (8.5%) were detected in the oil B. The oils demonstrated significant inhibitory (80% and 60.0%) potentials on acetylcholinesterase (an IC50 of 0.74 mg/mL and an IC50 of 1.78 mg/mL, respectively) which is involved in Alzheimer’s disease. With respect to antidiabetic activity, the oils demonstrated significant inhibiting potential on porcine pancreatic α-amylase (an IC50 of 1.02 mg/mL and an IC50 of 0.89 mg/mL) in I2/KI assay. The oils demonstrated weak free radical scavenging activity against DPPH radicals and moderate activity (0.23 mM and 0.15 mM) against ABTS+• in TEAC assay.