Purpose: Much of prior research focused on the dimensionality of the part of Job Diagnostic Survey that measures the core job characteristics, with mixed findings. The purpose of this paper is to develop and validate an instrument assessing core job characteristics. Design/methodology/approach: Public school teachers (n=685) serving in elementary and secondary schools filled in the Core Job Characteristics Inventory (CJCI). CJCI comprises 29 items to assess job autonomy, task significance, task identification, skill variety and feedback from the job. The development of the CJCI undergone the following stages: development of an initial pool of items, examination of its content validity by ten experts and a pilot study. Findings: Exploratory factor analysis revealed five factors with satisfactory internal consistency. Confirmatory factor analysis showed mixed results. Application of exploratory structural equation modeling procedures revealed that a correlated five-factor model yielded an adequate fit to the data. Associations among the five work features were significant, positive and yielding moderate values. Correlations among the five-core job characteristics and two affective job responses (job satisfaction and emotional exhaustion) provided evidence of CJCI concurrent validity. Practical implications: Human resources managers can use CJCI to measure core job characteristics or to evaluate interventions in the work places. Originality/value: A new instrument was developed to measure core job characteristics, and to address previous shortcomings reported in the literature. The rigorous methodological procedure, which followed for the development of the CJCI combined with a cross-validation approach best guarantees its applicability.