Nanoparticles of noble metals such as gold, platinum and especially silver are widely applied in medical and pharmaceutical applications. In this study silver nanoparticles have been synthesized through physical method where the Nd-YAG laser has been used , using pure silver in distilled water. By varying the processing conditions, the diameter of the silver nanoparticles was controlled between ~90 nm to ~101 nm. Spectrophotometer, Atomic Force Microscope, Atomic Absorption Spectroscopy have been used to reveal the formation and the corresponding morphology of the silver nanoparticles. Besides, the ablation efficiency of PLAL process was determined in term of the spectrum absorption peak of silver nanoparticles, high spectrum absorption peak was evidence to increasing the concentration of nanoparticles and high ablation efficiency. The silver nanoparticles production in 1064 nm laser wavelength was more efficient than production in 532 nm and 355 nm, The laser wavelength of 355 nm was more efficient than 532 nm in fabricating nanoparticles in distilled water. Therefore, the sample prepared at pulse repetition rate 6 Hz was more efficient than at 1 Hz, the number of ablation events increased and thus the number of particles generated. Also, the ablation efficiency for silver nanoparticles prepared at laser energy 760 mJ was more efficient than at 500 mJ. These absorption processes increased as number of particles increased in the solution. The result indicated that the effects of number of pulses on silver nanoparticles in 400 pulses were higher than that in 200 pulses. The absorption processes increased as number of particles increase in the solution. V The antimicrobial activities of silver nanoparticles were investigated on two types of bacteria Escherichia coli and Staphylococcus aureus. These bacteria were used as representatives of Gram-negative and Gram-positive bacteria; respectively .Two experiments have been made. The first one was to test the effectiveness of silver nanoparticles as an antimicrobial agent on gram negative bacteria Escherichia coli and gram positive bacteria Staphylococcus aureus , while the other one(susceptibility test) was to evaluate antimicrobial agents effective against bacteria resistant to multiple antibiotics. The result showed that the size and size distribution of silver nanoparticles can be controlled by varying the parameters of laser.