6-(4-Iodophenyl)amino-7-chloro-5,8-quinolinedione (RCK9) was evaluated for antifungal activities. The MIC values of RCK9 were determined against A. flavus, c. albicans, C. neoformans and F. oxysporium. The RCK9 showed generally potent antifungal activities against the tested fungi. Acute oral toxicity studies of RCK9 were carried out in ICR mice of both sexes. These acute oral toxicities of RCK9 had been evaluated. RCK9 were low and LD50 values were over 2,850 mg/kg in ICR mice. The genotoxicities of RCK9 had been evaluated. RCK9 was negative in Ames test with Salmonella typhimurium and chromosomal aberration test in CHL cells. The clastogenicity was tested on the RCK9 with in vivo mouse micronucleus assay. RCK9 did not show any clastogenic effect in mouse peripheral blood and was negative in mouse micronucleus assay. The results indicate that RCK9 has no genotoxic potential under these experimental conditions.