This case report presents a school-aged student who developed transient proteinuria after short-term use of methylphenidate (Ritalin) for enhancing concentration during examination periods. Methylphenidate (Ritalin) is commonly used for managing Attention Deficit Hyperactivity Disorder (ADHD). This case report highlights a rare adverse effect—proteinuria—in a young female who intermittently used Ritalin during academic exam periods. While initial short-term use in elementary school which was prescribed by a child psychiatrist due to suspected attention deficit showed no clinical symptoms or abnormal laboratory findings, repeated use in high school was associated with mild to significant proteinuria, which resolved after discontinuation. This case suggests a possible reversible nephrotoxic effect of Ritalin, warranting further investigation and cautious monitoring. [2,3]