Silver nanoparticles has received a lot of attention recently due to its certain features, and has been used in a variety of medical fields and treatments, therefore, the purpose of this work was to, ascertain how some cystic stages of intestinal protozoan parasites are affected by bacterial biosynthesized silver nanoparticles (AgNPs). The AgNPs were synthesized using Bacillus cereus and Chromobacterium violaceum bacteria. The AgNPs production was confirmed by several tests and techniques such as a UV-visible spectrophotometer, a fourier transmission infrared spectrophotometer (FTIR), and scanning electron microscopy (SEM), cysts of Entamoeba histolytica/dispar, Entamoeba coli, Giardia lamblia were obtained from human stool samples. The cystic stages were purified by density gradient sucrose solution and incubated with produced silver nanoparticles at (25, 75 µl/ml). With a significant difference between the two studied bacterial species, the biosynthesized silver nanoparticles significantly inhibited all cysts belonging to the study parasites. The effect of the silver nanoparticles produced by C. violaceum was less than the effect of the nanoparticles produced by B. cereus, especially on G. lamblia cysts. A significant effect of 23.9 % was noted for Giardia cysts, which was higher than the inhibition rates of 18.9 and 17.4 % for each of the cysts of E. hitolytica and E. coli, respectively. The inhibition rate was 16.67%, which was equal to the effect of metronidazole and higher than the effect seen with cysts of E. coli and E. histolytica. Based on the findings of the current study that silver nanoparticles have an inhibitory aspect on intestinal protozoan cysts, especially with larger doses than those used in the current experiment, silver nanoparticles use in treatment or decontamination procedures may be recommended.