Using a self-determination theory (SDT) framework, the aims of our study were to examine the perfectionism-exercise dependence relationships, and whether basic psychological needs and introjected regulation explained these relationships. Distance runners ( n  = 260, M age: = 42.41 years; SD: = 11.95 years, n  = 144 female) completed measures of multidimensional perfectionism (self-oriented perfectionism (SOP); socially prescribed perfectionism (SPP)), basic psychological need satisfaction and thwarting, introjected regulation, and exercise dependence. Bivariate correlations revealed significant positive SOP-exercise dependence and SPP-exercise dependence relationships. Structural equation modelling suggested that, in combination, perfectionism, basic psychological need satisfaction/thwarting and introjected regulation accounted for large amounts of variance in exercise dependence. Tests of indirect effects showed that the SPP-exercise dependence relationship was mediated by basic psychological need thwarting and introjected regulation. Our findings suggest that while the SOP-exercise dependence relationship is more direct, need thwarting and introjected regulation represent a motivational signature of SPP and exercise dependence.