Abstract: Plantago ovata (Plantaginaceae) and Oliveria decumbens (Umbliferae) are of important medicinal plants in Iran which have been used in traditional medicine. The aim of present study was to consider antibacterial properties of ethanolic and methanolic extracts of seed husk of Plantago ovata and aerial part of Oliveria decumbens. For this purpose, the 50 to 400 mg mL-1 concentration of these extracts were assayed against six Gram-negative and eight Gram-positive bacteria by disc diffusion method. Synthetic Antibiotic discs were used as control. Staphylococcus epidermidis and Staphylococcus aureus were the most sensitive species to the ethanolic and methanolic extracts of Plantago ovata while Pseudomonas aeruginosa was the most resistant to these extracts. Furthermore, Escherichia coli and Proteus mirabilis have shown resistance to ethanolic extract of this plant. Ethanolic extract of Oliveria decumbens was effective against all of tested bacteria and S. aureus was the most sensitive strain. In the case of the methanolic extract, Salmonella typhi, P. aeruginosa and P. mirabilis were more resistant than the others. The MIC (Minimal Inhibitory Concentration) and MBC (Minimal Bactericidal Concentration) values for Oliveria decumbens extracts against S. aureus were same (20 mg mL-1), whereas against Streptococcus pyogenes were different. Also, MIC for ethanolic extract of Plantago Ovata against S. aureus and Bordetella bronchiseptica were same (20 mg mL-1), whereas for methanolic extract were 20 and 10 mg mL-1, respectively. The MBC for these two bacteria weren’t found (>200 mg mL-1). On the basis of these results it can say that these plants have proper antibacterial effect and can be considered as a new source of antibiotic discovery and development for infectious disease treatment purposes.