The virucidal effects of ultraviolet (UV) irradiation, heat treatment and disinfectants against koi herpesvirus (KHV) were evaluated using KF-1 cells. KHV (KHV-I strain) was completely inactivated by UV irradiation at a dose of 4.0 × 10³ μ Ws/cm² or heating to temperatures above 50°C for 1 min. KHV was completely inactivated by 200mg/L iodophor, 60 mg/L benzalkonium chloride solution or 30% ethyl alcohol for 20 min. When chlorine concentration was measured after mixing with virus supernatant containing medium and fetal bovine serum, 97.5%and 98.5%reduction in infectivity was observed at 0.30 mg/L of chlorine for 30 s and 20 min, respectively. In practice, a tenfold concentration of chlorine (i.e.3 mg/L) will be recommended to inactivate KHV completely.