The diagnosis of pustular dermatosis occurring during the first months of life is usually based on clinical findings. However, some cases may require a few simple investigations including cytological studies, cultures, and skin biopsies. The most common causes of infectious pustular skin lesions include bacterial infections, which may be septicemic (with Listeria as the leading causative agent) or initially localized (staphylococcus); viral infections (varicella, herpes); fungal infections, i.e., candidiasis (congenital or neonatal) or the very recently described form of pustulosis due to Malassezia furfur; or parasitic (scabies). The main benign transient neonatal forms of pustulosis include infantile acropustulosis (for which the relationship with scabies is discussed), toxi-allergic erythema, transient pustular melanosis, and neonatal acne. Lastly, rare causes of neonatal pustulosis are reviewed. The need for investigating every neonate with skin pustules for an infectious disease, especially due to a bacterium, is emphasized.