Parental influences on youth drinking are well documented but not the influence of extended family members. This article explores extended family influences on alcohol use among Mexican youths and whether extended family members can be considered natural mentors. We conducted a qualitative study using ethnographic open ended interviews with 117 first year university students in Mexico City. The ethnographic interviews revealed six drinking groups: excessive, heavy, regular, occasional, abstainers and non drinkers. Youths reported close relationships with extended family members who provided counsel and acted as representatives of familial norms and values. The alcohol beliefs and behaviors of these family members, including their alcohol misuse, had a positive influence on youths' alcohol attitudes. The naturally occurring mentoring relationships of Mexican extended family members can positively influence moderate youth drinking. Natural mentoring relationships should be encouraged and facilitated in prevention efforts for Mexican youths, Mexican-American youths and potentially other Hispanic/Latino youths.