Abstract : The emergence of multidrug-resistant (MDR) bacteria pushes the researchers to investigate additional antibacterials. Mostly, medicinal plants are considered as the first source to search such agents. Many previous reports affirmed antibacterial and antibiofilm activities of Eucalyptus camaldulensis and Allium sativum extracts, but the activities of their mixture’s extracts have not been yet elucidated. This study was aimed to investigate the synergistic antibacterial and antibiofilm activities of E. camaldulensis and A. sativum mixtures’ extracts against MDR bacterial isolates of S. aureus, K. pneumoniae, E. coli and P. aeruginosa. According to the solvent and method of extraction, three extracts of each plant were prepared: methanol extract by maceration (MM), methanol extract by ultrasonic extractor (MU), and aqueous extract by an ultrasonic extractor (AU). Minimum inhibitory concentration (MIC), minimum bactericidal concentration, viability, and the biofilm inhibition activity of each extract were tested. All the nine extracts were showed notable activities towards the tested bacteria. Extracts of the mixture of both plants showed the highest activities against bacterial growth, viability, and biofilm formation activity. Methanol extract of the mixture of E. camaldulensis and A. sativum extracted by an ultrasonic extractor showed the highest activities against bacterial growth, viability, and biofilm formation. However, the synergistic antibacterial and antibiofilm activities were concluded.