Aims To test a nitric oxide-releasing solution (NORS) as a potential antifungal footbath therapy against Trichophyton mentagrophytes and Trichophyton rubrum during the mycelial and conidial phases. Methods and Results NORS (sodium nitrite citric acid) produces nitric oxide verified by gas chromatography and mass spectrometry (GC-MS). Antifungal activity of this solution was tested against mycelia and conidia of T. mentagrophytes and T. rubrum, using 120 mmol l-1 nitrites and 1030 min exposure times. The direct effect of the gas released from the solution on the viability of those fungi was tested. NORS demonstrated strong antifungal activity and was found to be dose and time dependent. NO and nitrogen dioxide (NO2) were the only gases detected from this reaction and are likely responsible for the antifungal effect. Conclusions This in vitro research suggests that a single 20-min exposure to NORS could potentially be used as an effective single-dose treatment against fungi that are associated with tinea pedis in both mycelia and spore phase. Significance and Impact of the Study This study provides the background for developing a user-friendly footbath treatment for Athlete's Foot that will kill both vegetative fungi and its spores.