Background: Neglect is the most common form of child maltreatment with consequences that appear to be as serious as for abuse. Despite this, the problem has received less than its due attention. Objective: To examine the relationship between the timing and chronicity of neglect during childhood and substance use in early adulthood. Participants and setting: The sample consisted of a subset of 475 participants from the prospective Longitudinal Studies of Child Abuse and Neglect (LONGSCAN) consortium from five geographic areas around the U.S. Method: Neglect was assessed using abstracted information from CPS reports (birth-18) and self-reports of neglect (12-18). Participants completed a follow-up online survey (mean age of 24 years) that probed their use of substances. Results: The prevalence of substance use during the past year was comparable in this high-risk sample to the general population. Latent class analysis supported the presence of three groups related to the presence and timing of neglect: Chronic Neglect, Late Neglect and Limited Neglect. Late Neglect was the pattern most strongly linked to substance use in early adulthood. Conclusions: High-risk youth experiencing neglect beginning in mid- adolescence are especially vulnerable to later substance use. Those working with such youth and their families can play a valuable role helping ensure their basic needs are adequately met, and recognizing early signs of substance use and abuse. Copyright 2019 Elsevier Ltd