Bipolar mood disorder (BPD) may manifest as the first episode of mania as early as below 6 years old. There are controversies regarding its diagnoses as because of sharing of symptoms with disruptive mood dysregulation disorder (DMDD), attention deficit hyperactivity disorder (ADHD) and conduct disorder. Hypersexuality was found to be a prominent feature in early-onset bipolar disorder (EOBD). Here is a case report of first episode mania in a child of 4.5 years old with a prominent feature of hypersexuality who responded well with valproate and risperidone.