The essential oil obtained from the aerial parts of Marrubium deserti de Noé. (Lamiaceae), growing in the North fringe of the Algerian Sahara, was analyzed by GC-MS. Thirty-eight compounds were identified, representing 99.70% of the total oils. The GC-MS analysis revealed the presence of tetracosane, germacrene D, Δ-cadinene, a-cadinol and t-cadinol as the main constituents, representing 31.11%, 7.91%, 6.52%, 6.26% and 5.81%, respectively. Minimum inhibitory concentrations (MICs) of essential oil and methanol extract were calculated by microtitre broth dilution method, and antibiofilm effects by microplate biofilm assay. The highest antibiofilm activity was found to be 69.31% against Micrococcus luteus NRRL B-4375 at 25 mg/mL for methanol extract and 36.62% against Candida albicans ATCC 10239 at 25 μL/mL concentration for essential oil. The antioxidant activity was determined using three complementary tests namely: β-carotene-linoleic acid, DPPHfree radical scavenging, and CUPRAC assays. In β-carotene-linoleic acid assay, both the oil and the extract exhibited good lipid peroxidation inhibition activity, demonstrating 76.81 ± 0.59 and 86.33 ± 0.27% at 200 μg/mL concentration, respectively. In DPPH and CUPRAC assays, however, the methanol extract exhibited high antioxidant activity; however, the essential oil showed weak activity. The in vitro anticholinesterase activity, was carried out against acetylcholinesterase and butyrylcholinesterase enzymes spectrophotometrically using Elman method. Methanol extract showed weak acetylcholinesterase and butyrylcholinesterase inhibitory activities, while the essential oil was inactive against both enzymes.