To　investigate　the　effect　of　1800　MHz　electromagnetic　radiation　(EMR)　on　apoptosis,　we　exposed　NIH/3T3　cells　at　1800　MHz　with　a　specific　absorption　rate　(SAR)　of　2　W/kg　intermittently　for　12,　24,　36,　and　48　h.　After　exposure,　Cell　Counting　Kit-8　(CCK-8)　and　flow　cytometry　were　used　to　detect　cell　viability　and　apoptosis;　the　expression　of　p53,　a　molecule　with　the　key　role　in　apoptosis,　was　measured　by　real-time　qPCR,　western　blot,　and　immunofluorescence;　and　images　of　the　structure　of　the　mitochondria,　directly　reflecting　apoptosis,　were　captured　by　electron　microscopy.　The　results　showed　that　the　viability　of　cells　in　the　12,　36,　and　48　h　exposure　groups　significantly　decreased　compared　with　the　sham　groups;　after　48　h　of　exposure,　the　percentage　of　late　apoptotic　cells　in　the　exposure　group　was　significantly　higher.　Real-time　qPCR　results　showed　that　p53　mRNA　in　the　48　h　exposure　group　was　1.4-fold　of　that　in　the　sham　group;　significant　differences　of　p53　protein　fluorescence　expression　were　observed　between　the　exposure　groups　and　the　sham　groups　after　24　h　and　48　h.　The　mitochondrial　swelling　and　vesicular　morphology　were　found　in　the　electron　microscopy　images　after　48　h　exposure.　These　findings　demonstrated　1800　MHz,　SAR　2W/kg　EMR　for　48　h　may　cause　apoptosis　in　NIH/3T3　cells　and　that　this　apoptosis　might　be　attributed　to　mitochondrial　damage　and　upregulation　of　p53　expression.