OBJECTIVES:To determine, in a community-based sample of primary school-aged children meeting diagnostic criteria for attention-deficit/hyperactivity disorder (ADHD), (1) the proportion of children with ADHD treated with medication; (2) predictors of medication use; and (3) the association between medication use and psychological service utilization. METHODS:Grade 1 children with ADHD were recruited through 43 schools in Melbourne, Australia, using a two-stage screening and case confirmation procedure. Parent report of medication treatment, clinician diagnosis, and psychological service use were collected at ages 7 and 10 years. Medication use was analyzed by ADHD subtype. Predictors of medication treatment examined included ADHD symptom severity and persistence, externalizing comorbidities, poor academic performance, and social disadvantage. Unadjusted and adjusted logistic regression were used to identify the predictors of medication status. RESULTS:One hundred seventy-nine children with ADHD were recruited. At baseline, 17.3% had been clinically diagnosed with ADHD, increasing to 37.7% at age 10 years. At baseline, 13.6% were taking ADHD medications, increasing to 25.6% at age 10. Children with the combined and hyperactive-impulsive subtypes were more likely to be taking medication than those with inattentive subtype (age 7: p = 0.002; age 10: p = 0.03). ADHD symptom severity (Conners 3 ADHD Index) at baseline was concurrently and prospectively associated with medication use at both ages (both p = 0.01), and ADHD symptom severity at age 10 was also associated with medication use at age 10 (p = 0.01). Baseline area-level disadvantage was associated with medication use at age 7 (p = 0.04). At 10 years, children receiving medication were more likely, compared with those who were not, to be receiving psychological services (p = 0.001). CONCLUSIONS:In this study, only a minority of children meeting diagnostic criteria for ADHD were diagnosed clinically or treated with ADHD medication by age 10. The strongest predictors of medication treatment were ADHD symptom severity and area disadvantage.