OBJECTIVES: ADHD has become a much debated topic in the last few years. More attention and awareness for ADHD has led to an increase in incidence. Especially awareness for the subtype of ADHD where patients, mostly females, demonstrate predominantly inattentive symptoms, has increased. We determined the male/female incidence ratio of ADHD drug treatment in the Netherlands from 2000 until 2010. METHODS: From the PHARMO database, including amongst others, drug dispensing records of approximately 3.2 million inhabitants in the Netherlands, we selected patients with a first dispensing of ADHD medication including methylphenidate, atomoxetine and dexamphetamine in the period 2000-2010. For each calendar year, the male/female incidence ratio of ADHD drug use was determined by dividing the incidence among males by the incidence among females. Results were stratified by age groups. RESULTS:  Overall, the male/female incidence ratio of ADHD drug treatment decreased from 3.4:1 in 2000 to 1.6:1 in 2010, meaning a growing proportion of female patients. The largest decrease in the male/female ratio was observed among adolescents (13-18 years: from 4.5:1 in 2000 to 1.6:1 in 2010), followed by 9-12 year-olds (from 5.5:1 in 2000 - 2.7:1 in 2010)  and 0-8 year-olds (from 6.2:1 in 2000 - 3.5:1 in 2010). Among adults and seniors this ratio fluctuated from 0.9:1 to 2.1:1. Although the incidence among females has increased more over the years, the incidence among males remained higher throughout the study period. CONCLUSIONS: This study shows that the proportion of female patients starting ADHD drug treatment is increasing. This in  line with the increased awareness of ADHD among females.