Background and Purpose: biosynthesis of nanoparticles by candida albicans is considered one of the new methods to synthesize iron nanoparticles (FeNPs), and it has been presented in some significant industries and the medical fields, especially in the development of new antimicrobial agents in pharmaceutical industries, as an alternative to traditional antimicrobial agents. This paper focuses on the synthesis of iron nanoparticles, which are prepared by candida albicans, and the possibility of these prepared nanoparticles being an antimicrobial agent in vitro Materials and Methods: FeNPs are synthesized by iron salt using candida albicans. The prepared FeNPs suspension was tested using UV-visible spectroscopy and FTIR Fourier-transform infrared spectroscopy to identify the formation of FeNPs. The antimicrobial activity of prepared FeNPs suspension was confirmed on the plates (in vitro). Results: The data show that the synthesis of FeNPs using candida albicans is a suitable and safe compatible, less expensive, less time-consuming, stable, and eco-friendly method for producing a good concentration of FeNPs, with a concentration of 9.4 ug\ml representing the minimum inhibitory concentration for the inhibition of some pathogenic bacteria on the plate. Conclusion: The FeNPs prepared suspension has antimicrobial activity in vitro.