Aim: This study aimed to evaluate the antibacterial effect of hyaluronic acid ‎versus propylene glycol as a vehicle with double antibiotic (ciprofloxacin and ‎metronidazole) paste against bacterial strains commonly found in non-vital primary ‎molar roots using agar diffusion method.‎ Materials and Methods: bacterial swap was taken using a sterile paper point ‎size 20 from a non-vital root canal of a lower second primary molar to isolate the ‎most common bacterial strains (staph aureus and Enterococcus faecalis) found in the ‎root canal, The two bacterial strains were cultured in Brain Heart Infusion (BHI) ‎broth to be used in the agar inhibition test. Subsequently, a sterile cork borer was ‎used to aseptically create a hole with a diameter ranging from 6 to 8 mm. Then, a ‎volume of the double antibiotic paste ciprodiazole (consisting of ciprofloxacin ‎‎500mg and metronidazole 500mg) combined with various vehicles to get the ‎necessary creamy consistency was inserted into the hole. Inhibition zone formed ‎around the well was measured (diameter) and recorded in millimeters using calipers ‎and mean values were calculated. ‎ Results: For Staphylococcus aureus, values of inhibition zones formed with ‎hyaluronic acid vehicle were significantly higher than those of propylene glycol ‎‎(p<0.001). However, for Enterococcus faecalis, the difference was not statistically ‎significant(p=0.280).                                    Conclusions: Using hyaluronic acid as a vehicle with metronidazole and ‎ciprofloxacin could be a good safe substitute for propylene glycol with better ‎antibacterial effect on necrotic root canal bacterial strains.  ‎