A 6-month-old male Japanese domestic cat with otitis externa due to Aspergillus fumigatus was treated with antifungal agents for 25 days and appeared to be cured. Many yeast colonies however developed from the ear canal samples on Sabouraud's dextrose agar at 27 degrees C for 5 days, instead of A. fumigatus. This yeast colony was cream-colored and slim in texture with smooth and highly glossy surface after 5-day incubation on Sabouraud's dextrose agar at 27 degrees C. The isolate was identified as Cryptococcus magnus by mycological analysis and 28S ribosomal analysis.