This paper examined the conceptual and statistical distinction between perceived competence and self-efficacy. Although they are frequently used inter-changeably, it is possible that distinguishing them might assist researchers in better understanding their roles in developing enduring adaptive behavior patterns. Perceived competence is conceived in the theoretical framework of self-determination theory (Deci & Ryan, 2002) and self-efficacy in the theoretical framework of social cognitive theory (Bandura, 1986). Purpose: The purpose of this study was to statistically distinguish perceived competence from self-efficacy for exercise. Method: Two studies evaluated the independence of perceived competence and self-efficacy in the context of exercise. Using two extant instruments with validity and reliability evidence in exercise contexts, the distinctiveness of the two constructs was assessed in two separate samples (n=357 middle aged sedentary adults; n=247 undergraduate students). Results: Confirmatory factor analysis supported the conceptual and empirical distinction of the two constructs. Conclusions: This study supports the conceptual and statistical distinction of perceived competence from perceived selfefficacy. Applications of these results provide rationale for more precise future theorizing regarding their respective roles in supporting initiation and maintenance of health behaviors.Key words: exercise, factorial validity, motivation, need satisfaction.Perceived competence and self-efficacy for exercise -3 -Distinguishing Perceived Competence and Self-efficacy: An Example from Exercise Regular exercise is foundational to the maintenance of good health as well as rehabilitation and regulation of many disease conditions including coronary vascular disease, and type 2 diabetes (Bouchard, Blair & Haskell, 2007;Katzmarzyk, Church & Blair, 2004;Katzmarzyk & Janssen, 2004;Katzmarzyk, Janssen & Ardern, 2003). Public health practitioners are concerned with better understanding motivation to engage in regular exercise (e.g., Bauman, Nelson, Pratt, Matsudo, & Schoeppe, 2006;Bleich, & Sturm, 2009;Cavill & Bauman, 2004;Prohaska, Belansky, Belza, Buchner, Marshall, McTigue, Satariano, & Wilcox, 2006;Rychetnik, Bauman, Laws, King, Rissel, Nutbeam, Colagiuri, & Caterson, 2012). Social cognitive approaches to motivation for exercise all include some consideration of perceived capability to perform the focal behavior. The extent to which these conceptions of capability are distinguishable however is the topic of some debate. Theoretically and practically, it seems necessary to disentangle different conceptualizations because too many redundant variables clutter the literature, yet clearly distinguishable variables can contribute to a more fully explicated understanding of human behavior (Biddle, 2006;Forscher, 1963; Zhu, 2000). The idea that people need to perceive they are capable of performing a focal health behavior before they can be expected to adopt it seems logical. Self-determination theory (Deci & Ryan, 200...