Nannizziopsis guarroi is a cause of contagious dermatomycosis in lizards, and recently, snakes. The literature reports that treatment failures are common which may be related to the published environmental persistence of this microbe. F10 SC a commercially available disinfectant that contains the active ingredients benzalkonium chloride and polyhexanide, is often used by hobbyists and breeders to control and/or treat infections. Three aqueous suspensions of molecularly confirmed N. guarroi isolates were diluted to two fungal concentrations and then exposed to 3 dilutions of the disinfectant (1:20, 1:100, 1:500) for a 10-minute contact time. Characteristic colony growth and cytology was used to confirm culture growth after 10d of incubation on standard fungal media. Control conditions (H2O) and technical replication was performed. All control conditions grew characteristic fungal colonies (white fluffy growth) with fungal elements (arthroconidia and hyphae) visualized cytologically. All 3 isolates exhibited no growth after 10 minute contact time with the highest concentration of the disinfectant (1:20), regardless of fungal concentration whereas fungal growth was evident after contact with the lowest concentration of disinfectant (1:500) for each of the isolates. N. guarroi contaminated environments can be effectively disinfected using 1:20 dilution of F10 SC for a contact time of 10 minutes. This disinfectant dilution has not been shown to be safe when in contact with living tissue and cannot be recommended at this time. Our findings can be loosely extrapolated to other closely related fungi (Nannizziopsis spp., Parananniziopsis spp.) that cause disease in reptiles when evidence-based disinfection data is not available.