The current study examined the Career Thoughts Inventory (CTI (psychometric properties and its performance among a sample of 2366 adolescents; 1037 (45.4%) males and 1289 (54.5%) females. Item Response Theory (IRT) was applied to identify which CTI items proficiently contribute to a single proper measurement of CTI. IRT evaluates the amount of information for each item of the scale for each trait level on the trait dimension through the item information function. IRT allows the assessment of differential item functioning (DIF). Results showed that goodness of fit indices all supported the bi-factor model. IRT identified one problematic item. CTI was shortened to 22 and DIF showed two items endorsed differently between males and females. Limitations and discussions were discussed.