Objective: Substance use and childhood maltreatment experience are linked, but little is known about the association with polydrug use patterns. Method: Latent class analyses (LCA) were performed on eight illicit drugs in a random population sample of young Danes separated by sex (males: n = 1,555; females: n = 1,425). Logistic regressions explored associations of polydrug use patterns and childhood maltreatment. Results: A three-class solution best described patterns of polydrug use in both the male and female samples. Across all LCA models, Class 1 was characterized by individuals who represented wide-range polydrug users, endorsing many of the drug types (males = 8%; females = 2%). Class 2 was characterized by amphetamine, cannabis, cocaine, and amyl nitrate users (males = 18%; females = 7%). Class 3 was characterized by individuals who endorsed either low-level use of cannabis only or no drug use (males = 74%; females = 91%). For males, having been a child-protection case was associated with Classes 1 and 2 and for females with Class 2, compared with Class 3. Alcohol problems were associated with Classes 1 and 2 for both sexes. Sexual abuse was associated with Classes 1 and 2 for females but not males, whereas physical abuse was associated with Classes 1 and 2 for males but not females, as compared with Class 3. Conclusions: Separate sex analyses are important; although patterns of polydrug use are broadly similar, females are less frequently polydrug users. In addition, different relationships exist for the sexes, such that polydrug use patterns are associated with sexual abuse in females, whereas such patterns are associated with physical abuse in young males.