Aim: This study inquires into identity alteration among college students and its relationship to borderline personality disorder (BPD) and/or dissociative disorders (DDs). Methods: Steinberg Identity Alteration Questionnaire (SIAQ), Childhood Trauma Questionnaire (CTQ), and self-report screening tool of the BPD section of the Structured Clinical Interview for DSM-IV (SCID-BPD) were administered to 1301 college students. Participants who fit the diagnostic criteria of BPD (n=80) according to the clinician-administered SCID-BPD and 111 non-BPD controls were evaluated using the Structured Clinical Interview for DSM-IV DDs (SCID-D) by two psychiatrists blind to the group membership and scale scores. Results: Test-retest evaluations and internal consistency analyses suggested that SIAQ was a reliable instrument. Of the participants, 11.3% reported a SIAQ score 25 or above alongside some impairment. SIAQ scores differentiated participants who fit the diagnostic criteria for a DD from those who did not. While self-report identity alteration was correlated with all childhood trauma types, clinician-assessed identity alteration was correlated with childhood sexual abuse only. Those who fit criteria for both disorders had the highest identity alteration scores in self-report and clinician-assessment. Although both syndromes had significant effect on self-report identity alteration total scores, in contrast to DD, BPD did not have an effect on the clinician-administered evaluation. Conclusion: An impression of personality disorder rather than a DD may seem more likely when identity alteration remains subtle in clinical assessment, notwithstanding its presence in self-report. Lack of recognition of identity alteration may lead to overdiagnosis of BPD among individuals who have a DD.