Nasal obstruction is a very frequent symptom in children, with numerous etiologies. Clinical diagnosis is straightforward, but general impact and rare etiologies should be explored for. Complementary examinations are guided by diagnostic orientation. Although not usually a severe condition, nasal obstruction may be life-threatening in neonates and infants. An exhaustive list of etiologies is impossible and would not be useful, but it is worth distinguishing infantile nasal obstruction and nasal obstruction in older children, as causes differ greatly. This is the topic of the present update.