Issues in applied survey research, including minimizing respondent burden to encourage survey completion and the increasing administration of questionnaires over smartphones, have intensified efforts to create short measures. We conducted two studies to examine the psychometric properties of single-item measures of four close-relationship variables: satisfaction, love, conflict, and commitment. Study 1 was longitudinal, surveying an initial sample of 121 college-age dating couples at three monthly phases. Romantic partners completed single- and multi-item measures of the four constructs, along with other variables, to examine test-retest reliability and convergent (single-item measures with their corresponding multi-item scales), concurrent, and predictive validity. Our single-item measures of satisfaction, love, and commitment exhibited impressive psychometric qualities, but our single-item conflict measure performed somewhat less strongly. Study 2, a cross-sectional online survey (n = 280; mainly through Facebook), showed strong convergent validity of the single-item measures, including a .60 correlation between single- and multi-item conflict measures.