The irrational use of antibiotics has caused an increment in bacterial resistance to these compounds, leading humans to go in quest of alternative effective antimicrobial factors with less side effects as compared to antimicrobial compounds with less unwanted side effects. Silver Nanoparticles (AgNPs) could be considered as one of the most important antibacterial agents. In this study, the aqueous extract of Fumaria officinalis leaf was prepared and used in optimal conditions(pH=10, extract volume=8, metal salt concentration=10 mM, temperature 100 °C and time=120 min) for reduction of silver ions and synthesis of AgNPs. The resulted AgNPs were characterized by different techniques including UV-Vis, and XRD, FESEM, TEM, EDX and FTIR, respectively. Finally, the antibacterial activity of AgNPs on two pathogens (Escherichia coli (PTTC 1707), and Staphylococcus aureus (PTTC 1112)), was investigated using agar disk diffusion and minimum inhibitory concentration (MIC) test. The extract of Fumaria officinalis displayed high potential to synthesize of stable spherical AgNPs in shape with size below 25 nm. The nanoparticles showed considerable antibacterial effect on two tested bacteria. The minimum inhibitory concentration on Escherichia coli and Staphylococcus aureus for AgNPs was 12.5 and 6.25 μg / ml, respectively.