Abstract: The purpose of this investigation was to explore the frequency and nature of ungual alterations in patients of a pediatric dermatology department at a third‐level pediatric hospital. The first 20 patients with nail alterations seen each year during a 5‐year period from 1992 through 1996 were included, totaling 100 patients. The rate of nail alterations was 11% (1/9) in pediatric dermatology patients. There were 5 infants, 19 preschoolers (2‐ to 5‐year‐olds), 38 school children (6‐ to 11‐year‐olds), and 38 adolescents (12‐ to 17‐year‐olds). The most frequent diagnoses were onychomycosis (23), nail alterations in a genodermatosis (23), nail alterations associated with dermatoses (16), onychocryptosis (11), and paronychia (10). Toenails were involved in 54 patients, fingernails in 25, and both in 21 patients. Twenty nails were involved in 21 patients. A high prevalence of nail alterations was found in pediatric dermatology patients, some of which were nonspecific, while others provided important diagnostic clues.