Indiana University-Purdue University Indianapolis (IUPUI) / Background: Research has repeatedly shown that individuals with severe mental illness desire interpersonal and romantic relationships and that social support (including spousal relationships) is beneficial. In addition, social deficits in mental disorders can often get in the way of developing fulfilling relationships. However, there is little currently available to help clinicians and researchers assess romantic relationship functioning in those with mental illness. The aim of this pilot study was to examine reliability and validity of a new measure of functioning in romantic relationships, the Romantic Relationship Functioning Scale (RRFS). Method: The RRFS was constructed based on theory proposed by Redmond, Larkin, and Harrop (2010). In an analog study, we tested the measure in a sample of college students (N=387), examining reliability, stability over time, factor structure, and relationships with measures of psychopathology and related measures of social functioning to assess convergent validity. Results: The RRFS exhibited a hierarchical four-factor structure, supporting the use of a total score. Although subscales were supported in the factor analysis, other psychometric evidence was weaker, and the use of a total score is advocated. Internal consistency and test-retest reliability were acceptable for the total scale (>.8). The RRFS had moderate to large correlations in the expected direction with all psychopathology measures. In predictive models, overall mental health, social functioning, and fewer interpersonal difficulties predicted higher romantic relationship functioning. Conclusions: The RRFS total score shows preliminary evidence of reliability and validity. The RRFS has potential to be of use in treatment centers for undergraduates and for individuals with diagnosed mental disorders. Future research should further investigate the RRFS subscales and the measure’s performance in clinical samples.