Synthesis of novel cyclopropyl pyrimidine and purine nucleoside derivatives 2~8 with ${alpha}$-configuration was successfully accomplished using an epoxide-ring opening reaction, lactonization, a hydroboration-oxidation reaction and a Mitsunobu reaction as the key steps. Antiviral activities against HSV-1 and -2, HIV-1 and -2, coxsackie B1and B3 viruses and poliovirus were assayed. Three compounds 4, 7 and 8 exhibit cytotoxicity-derived antiviral activity only in HIV-1 and -2.