This study aimed to identify features of breast intraductal lesions in photoacoustic/ultrasound (PA/US) imaging and compare PA/US with color Doppler flow/ultrasound (CDFI/US) in the evaluation of breast intraductal lesions. In the nine patients with 10 breast intraductal lesions and 8 patients with 8 benign lesions, total vessel scores evaluated from PA/US are significantly greater than those from CDFI/US (p=0.005). PA internal vessel scores and oxygen saturation (SO₂) score are significantly increased in breast intraductal lesions than in benign lesions (p=0.016, p=0.006). With a cutoff PA score (sum of PA internal vessel score and SO₂ score) of 2.5, we obtained a sensitivity of 90% and a specificity of 87.5% in differentiation of two groups. PA/US upgraded 40% of breast intraductal lesions, and downgraded 50% of benign lesions from the Breast Imaging Reporting and Data System grading results based on CDFI/US. PA/US functional imaging has the potential in differentiating breast intraductal lesions.