The results of space radiation experiments carried out on board the first two Korean technology demonstration microsatellites are presented in this paper. The first satellite, KITSAT-1, launched in August 1992, carries a radiation monitoring payload called cosmic ray experiment(CRE) for characterizing the low-earth orbit(LEO) radiation environment. The CRE consists of two sub-systems: the cosmic particle experiment (CPE) and the total dose experiment(TDE). In addition, single event upset(SEU)rates of the program memory and the RAM disk are also monitored. The second satellite, KITSAT-2, launched in September 1993, carries a newly developed 32-bit on-board computer(OBC), KASCOM(KAIST satellite computer in addition to OBC186. SEUs ocurred in the KASCOM, as well as in the program memory and RAM disk memory, have been monitored since the beginning of the satellite operation. These two satellites, which are very similar in structures but different in orbits, provide a unique opportunity to study the effects of the radiation environment characterized by the orbit.