The purposes of this study were to develop a Japanese version of the multi-dimensional Work-Family Conflict Scale (WFCS) and to examine its reliability and validity. The original 18-item WFCS (Carlson, et al., 2000) has six dimensions of conflict which consist of time-based work interference with family (WIF), time-based family interference with work (FIW), strain-based WIF, strain-based FIW, behavior based WIF, and behavior-based FIW. We developed a Japanese version of the WFCS from the original WFCS which is written in English by the following procedure: forward translation and back translation by several researchers including a native English speaker, and finally, gaining the approval of Carlson et al., the original authors. A self-administered questionnaire including the WFCS was distributed to 180 permanent contract, information technology (IT) engineers with pre-school children, who were employed at 24 IT companies, each with over 300 employees. Test-retest was conducted on a different group of 34 parents whose children were attending nursery school. Cronbach's reliability coefficients for the six subscales ranged from 0.77 to 0.92, showing sufficiently high internal consistency. Only the internal correlation coefficient between behavior-based WIF and behavior-based FIW was above 0.60, indicating that discriminant validity exists among most of the sub-scales. Also, upon comparison of confirmatory factor analysis results among five models, the six-factor model, which is the same model used in the original WFCS, showed the best fit (chi-square=231.82, df=129, CFI=0.95, AIC=315.82, RMSEA=0.07), demonstrating construct validity. On test-retest, weighted kappa coefficients of each item and the intra-class correlations of six subscales, indicated adequate reproducibility. These results suggest that the Japanese version of the WFCS may be a reliable and valid instrument for assessing the conflict between work and family in Japanese workers.