Objective: There are no valid assessment instruments assessing fertility intention among breast cancer survivors in mainland China. Therefore, this study aims to examine the psychometric properties of the Taiwanese version of the Fertility Intention Scale (FIS) among female patients with breast cancer of childbearing age in mainland China. Methods: Two hundred and sixty-four female patients with breast cancer of childbearing age were recruited from two tertiary hospitals in Tianjin and Baoding, of which 32 patients completed the survey twice. Confirmatory factor analysis was adopted to assess construct validity. Correlations between the Reproductive Concerns After Cancer scale and FIS scores were calculated using Spearman correlation for convergent validity. The known-group validity of the FIS was verified using Mann-Whitney U test to compare the FIS scores between patients with or without the intention to conceive. Moreover, reliabilities were examined using Cronbach's alpha and intra-class correlation coefficient. Results: Confirmatory factor analysis showed a good model fit to previous factor structures (chi(2)/df = 3.19, root mean square error of approximation = 0.091, comparative fitting index = 0.980, Tucker-Lewis index = 0.975), and no FIS item was dropped. The FIS scores were weak negatively correlated with the Reproductive Concerns After Cancer scale scores (r = -0.172, P < 0.01). The convergent validity of FIS was not satisfactory. Differences were noted between patients with or without the intention to conceive (50.62 +/- 6.35 vs. 45.98 +/- 7.19, P < 0.01). The FIS showed acceptable known-group validity. The internal consistency (Cronbach's alpha = 0.824) and the test -retest reliability (r = 0.863, P < 0.01) of the FIS were also acceptable. Conclusions: Overall, the FIS provides a comprehensive evaluation of the fertility intention among patients with breast cancer of childbearing age in mainland China. However, the convergent validity was not satisfactory; thus, further revision and validation may be required in the future.