In the recent past, biosorbents of biological origin such as bacteria, algae, and fungus have found a specific application in the solid phase extraction as an alternative column packing material. It is feasible to use them in the column after their immobilization onto a convenient support material. In the present work, alternative biosorbent Coriolus versicolor immobilized γ‐Fe2O3 nanoparticles (NPs) were prepared for the preconcentration of trace amounts of Ag(I) in environmental samples. The surface structure of C. versicolor immobilized γ‐Fe2O3 NPs were identified via the Fourier transform infrared spectroscopy, the scanning electron microscope, and the energy dispersive X‐ray. Experimental parameters were investigated. The following elution with 1 mol/L HCl, Ag(I) was measured by an inductively coupled plasma optical emission spectrometer. The limit of detection, limit of quantitation, and preconcentration factor were achieved as 0.0018, 0.0062 ng/ml, and 100, respectively. The biosorption capacity of the biosorbent was found as 31.7 mg/g. In addition, γ‐Fe2O3 NPs without C. versicolor were tested and the results showed that the recovery value of Ag(I) was lower than 25%. The efficiency of the method was tested through recovery measurements of certificated reference materials and high recoveries (≥95%) with low‐relative standard deviation were obtained. Additionally, it was successfully used for the quantification recovery of Ag(I) in spiked environmental samples. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13151, 2019