Nail disorders in children and newborns are frequently encountered in daily practice and are often challenging to diagnose. They may be congenital and hereditary or acquired. Nail signs may be present at birth or develop during neonatal life or later and may occasionally be part of a syndrome or a systemic disorder. Nail dermatoscopy (onychoscopy) has become a routine diagnostic instrument, since it provides helpful information. In daily practice, it can be a valuable tool to clarify common findings of specific diseases, thereby supporting clinical diagnoses and guiding the management and prognosis of various nail conditions. In the first part of the chapter, we explain the technique and the problems of nail dermatoscopy and will give tips to the reader to perform this exam on the nails in pediatric population. In the second part, we will show how to identify the normal nail with dermatoscopy followed by sections on the main features of the most commonly encountered nail diseases in children on the basis of specific signs.