The purpose of this study was to assess characteristics of a measure of monitoring the health of a dyadic relationship based on data from self-report surveys completed by both partners from dating heterosexual, married heterosexual, cohabiting gay male, and cohabiting lesbian couples from the United States (Ns = 127, 46, 81, and 224, respectively). Covariation among the measure’s 7 items conformed to 1 latent factor. Intraclass correlations between partners from the same couple were positive. Gender effects occurred only for married couples, with wives having higher scores than husbands. One’s own and one’s partner’s monitoring accounted for unique variance in one’s own commitment, even with controls for other variables. Monitoring buffered the negative effects of neuroticism on commitment.