A method for preconcentration of Al(III) prior to its determination by inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed because the sensitivity of ICP-OES is insufficient for trace-level measurement of Al(III). The method is based on the use of Coriolus versicolor-immobilized gamma-Fe2O3 magnetic nanoparticles as a solid phase sorbent. The best experimental conditions were found as pH 6.0, 2.0 mL/min flow rate, 100 mg amount of C. versicolor on 150 mg of gamma-Fe2O3 nanoparticles, and 500 mL of sample volume. The Al(III) absorbed on biosorbent was eluted with 5.0 mL of 1.0 mol/L HCl. Limit of detection, limit of quantitation, linear range, correlation coefficient, relative standard deviation, and preconcentration factor were achieved as 0.03 ng/mL, 0.11 ng/mL, 0.2 to 20 ng/mL, 0.9994, 3%, and 100, respectively. Al(III) was preconcentrated in different water and food samples after successful results were achieved in the case of certified reference samples.