Onychomycosis refers to nail infections, caused by fungi including yeasts and non-dermatophyte moulds. One or several toenails or fingernails (seldom all) may be involved in this condition. Many cases of fingernail onychomycosis are due to yeasts. Fungal infection has emerged as an important cause of neonatal infection, associated with significant morbidity and mortality, especially in very low birth weight (< 1500 g) and extremely low birth weight (< 1000 g) infants. Herein, we report a case of a 24-day-old male infant, who presented with onychomycosis on the left ring fingernail, associated with fungal urinary tract infection (UTI). The evaluation of nails helped us detect fungal UTI. To date, there have been no reports suggesting onychomycosis as a presentation of fungal UTI. We could not find the association between onychomycosis and neonatal fungal UTI. Hence, retrospectively, it can be said that onychomycosis was a presentation of fungal UTI. Further studies are required to evaluate the etiology and treatment of neonatal onychomycosis. Moreover, dermatologists should pay particular attention to this rare event.