In this case-control study of adult African Americans (n=476; 206 females, 270 males), we examined the association of the functional prodynorphin 68 bp (<i>PDYN</i> 68 bp) promoter repeats with categorical diagnoses of cannabis dependence (<i>Diagnostic and Statistical Manual of Mental Disorders-IV</i> criteria), as well as with a rapid dimensional measure of maximum lifetime cannabis exposure (the Kreek-McHugh-Schluger-Kellogg cannabis scale).