In this research, the aim was to apply the Occupational Field Interest Inventory (OFII), which was developed in paper-pencil format, as a Computerized Adaptive Test (CAT). For this purpose, the paper and pencil form of the OFII was applied to 1425 high school students and post-hoc simulations were carried out with the obtained data. According to results obtained from the simulations, it was decided that the most ideal criteria for the CAT application were GPCM as the IRT model, .40 standard error value as the test termination rule, and MFI as the item selection method. The OFII ended with an average of 59 items, and the correlations between scores obtained from the paper-pencil form and thetas (θ) estimated by simulation ranged between .91-.97. According to post-hoc simulation results, the CAT application was applied to 150 students. It was observed that the correlations between the scores of students from the online application of the paper-pencil form and θ levels estimated by the CAT form varied between .73 and .91.