Objective: The objective of this research is to provide the first empirical data to support the phenomenon of coprogression, which can be defined as the extent to which progressing toward healthy criteria on one behavior is associated with progressing toward healthy criteria on a second behavior at the same follow-up time point for individuals who met risk criteria for both behavior risks at baseline. Methods: Participants (N=9,461) were predominantly middle-aged (M= 43.9 years, SD=10.74), White (93.8%), and female (65.4%) adults from the United States who were proactively recruited by telephone. Each participant met criteria for both behavior risks at baseline and were assessed at 24-month follow-up for the following three behavior pairs: 1) smoking and diet, 2) smoking and unprotected sun exposure, and 3) unprotected sun exposure and diet. All participants were randomized to either the TTM-tailored treatment condition (N=4,800) or the assessment-only control (N=4,661). Results: Twenty-six out of 27 odds ratios (ORs) revealed that participants were more likely to progress toward healthy criteria on both behaviors in each behavior pair than progressing to criteria on only the second behavior in each behavior pair. Conclusion: The significant results and occurrence of 26/27 ORs being greater than 1.0 provide empirical support for including coprogression as a phenomenon in the emerging science of multiple health behavior change (MHBC).