Background: Attention deficit–hyperactivity disorder (ADHD) is a common neuropsychiatric disorder affecting children marked by inattention, hyperactivity, and lack of impulse control. Inflammation, a biological state, is characterized by elevated levels of acute-phase proteins, complement factors, cytokine cascades, and cellular immune responses (e.g., ESR and CRP). This study aimed to: Evaluate ESR and CRP as indicators of inflammatory processes in the pathogenesis of ADHD. And To evaluate ESR levels in the prediction of treatment response in children with ADHD. Methods: The study was a case-control study conducted at the Pediatric Department and Clinical Pathology Department, Minia University Children and Maternity Hospital, from April 2021 to April 2022. The hospital ethics committee approved this study, and written consent was obtained from each patient's caregiver. Subjects and methods: The children included in the study were divided as follows: Group 1: 40 children diagnosed with ADHD who had regular follow-up in the Pediatric Neuropsychiatric Outpatient Clinic of Minia University Children's Hospital. Their age ranged from 6 to 18 years. They were further divided into the following subgroups: Group 1A: 20 newly diagnosed children with ADHD who had not yet taken any medical treatment for ADHD. They were 90% male, 10% female, with an age range of 6-15 years (Mean ± SD = 8.15 ± 2.62). Group 1B: 20 previously diagnosed children with ADHD who had been under treatment with non-stimulant ADHD medication for at least 6 months. They were 70% male and 30% female, with an age range of 6-12 years (Mean ±SD = 8.15 ± 1.62). Group 2: 20 healthy children with matched age and sex to the children in group І. They were 65% male and 35% female, with an age range of 6-12 years (Mean ± SD= 9.15 ± 1.59). Results: There was a statistically significant difference in 1st hour ESR levels between the un-medicated and medicated ADHD groups compared to the healthy control group (P values = 0.0001, 0.0001, respectively). However, there was no statistically significant difference in CRP levels between the studied groups (p value = 0.121). Conclusion: ESR is used as an inflammatory marker in the follow-up of ADHD children.