The transition to adulthood is, in general, a difficult phase—one riddled with physical, mental, and social changes (Park, Kim, Kim & Sung, 2007; Votta & Manion, 2004). Among homeless youth, this transition is made more difficult due to circumstances of poverty, lack of support, exposure to violence and crime, and resulting mental health issues. For many, substance use is perceived as “self medication” as a support to deal with mental illness, as a social connection to peers and as a coping strategy when living on the streets (Christiani, Hudson, Nyamathi, Mutere, & Sweat, 2008). Compared to their non-homeless counterparts, homeless youth use substances earlier and with greater frequency (Barczyk & Thompson, 2008; Meade, Slesnick & Tonigan, 2001; Nyamathi et al., 2007; Park et al., 2007). While knowledge about correlates of heightened substance use is crucial for understanding homeless youth’s substance use and associated risk behaviors for HIV (Human Immunodeficiency Virus) and hepatitis B (HBV) and C (HCV) virus, the literature contains little information about such correlates among homeless youth. The purpose of this study is to assess correlates of substance use among homeless youth. Understanding these factors can lead to the development of targeted intervention programs that assist youth in areas that facilitate or discourage ongoing substance use. Although the literature on correlates of substance use among homeless youth is limited, sociodemographic information, peer and family influence, and childhood abuse have been identified as predictors of substance use among the general youth population (Martijn & Sharpe, 2006; Rew, Taylor-Seehafer, & Fitzgerald, 2001). Immutable factors, like race and gender, can forecast the frequency of substance use. For example, findings on ethnic and racial group differences in substance use among youth have been fairly consistent since the 1970s (Galanter, 2005). Native American youth reportedly have the highest use of alcohol (Galanter, 2005), followed by the Caucasian majority (Adams & Berzonsky, 2005; Miller & Carroll, 2006; Thompson, Kost & Pollio, 2003; Tyler & Torres-Stone, 2003). Hispanic youth consume alcohol the next most frequently, followed by African Americans (Adams & Berzonsky, 2005; Galanter, 2005; Tyler & Torres-Stone, 2003); Asian American youth have the lowest rate of alcohol use (Adams & Berzonsky, 2005; Miller & Carroll, 2006). Furthermore, African Americans have the highest rates of illicit substance use (Miller & Carroll, 2006). While racial/ethnic differentiation can sometimes predict future substance use among housed youth (Adams & Berzonsky, 2005; Miller & Carroll, 2006), few studies elaborate on whether such differences are found when comparing various ethnic groups of homeless youth (Rew et al., 2001). In terms of gender, regardless of race or other determinants, males are more likely than females to use alcohol and other drugs (Adams & Berzonsky, 2005; Galea, Nandi, & Vlahov, 2004; Park et al., 2007). Peer substance use and peer pressure often increase a youth’s substance use (Kim, Zane & Hong, 2002; von Sydow, Lieb, Pfister, Hofler & Wittchen, 2002). Prevalent drug and alcohol use within the youth’s social network strongly predicts self-reported substance use (Bousman et al., 2005; Galanter, 2005; Shaw, 2002). In fact, in a study of more than 2,000 high school students, social network characteristics were more responsible for explaining youth’s alcohol use than familial situations (Galea et al., 2004). At the opposite end of the social spectrum, youth without any social network also report heavy illicit substance use (Galanter, 2005), as substance use can serve as a coping mechanism for issues related to loneliness and resulting depression (Torres & Gore-Felton, 2007). Abuse within the family plays a significant role in predicting drug and alcohol use among youth. Families where relationships between parents and children are poor, where there is a sudden disruption in structure, or where other adverse conditions are present, often produce children with excessive alcohol and substance use (Adams & Berzonsky, 2005; Galea et al., 2004). Childhood abuse is one of the most serious risk factors for substance-using youth (Galanter, 2005; Park et al., 2007; Slesnick, Bartle-Haring, & Rashmi, 2006). In a recent study, the physical abuse rate of substance-using youth was six to 12 times higher than that of non-substance users (Park et al., 2007). Additionally, youth with alcohol abuse or dependence were 18–21 times more likely to have a history of sexual abuse than their counterparts without these alcohol problems (Park et al., 2007), underscoring the important link between victimization and substance use. Among homeless males, when these gender-dictated obligations of being self-sufficient and employed are not met, their self-esteem is lowered (LaGory et al., 2001), frequently leading to risky behaviors (Christiani et al., 2008). In addition, social networks and peers also play a large role in determining a homeless youth’s drug and alcohol use (Adams & Berzonsky, 2005; Galea et al., 2004; Shaw, 2002). Criminal involvement and academic failure have also been cited as predictors of homeless youth’s substance use (Barczyk & Thompson, 2008). However, the literature is inconsistent since schooling and the education domain have also been found to have only an indirect linkage to substance use (Kim et al., 2002). Such findings point to pain, trauma, and an inability to cope as predictors of drug and alcohol use (Slesnick, 2004). The difficult situations inherent in a homeless existence, including exposure to crime, victimization, a fluctuating family life, and impaired social networking, can have a great effect on a youth’s drug and alcohol use (Slesnick, 2004).