Periapical radiographs are intraoral radiographs that can provide clearer and more detailed information about the teeth and surrounding tissue. Based on the recommendations of the International Actomic Energy Agency (IEIA) and the Nuclear Energy Supervisory Agency (BAPATEN), the dose level for intraoral dental examination is 7 mGy. X-ray radiation produced by periapical radiographs can cause cell damage in the body, which one of the cells that is damaged is hematopoietic cells in the bone marrow. Purpose: The purpose of this study was to prove a decrease in thrombocytes (platelets), leukocytes, hemoglobin count and the value of Mean Corpuscular Volume (MCV) in mice (Mus musculus) due to X-ray radiation periapical radiographs. Method: This study was a true experimental design with a post test only with control group design that was given 1, 7, and 10 times the exposure of periapical radiographs of X-ray radiation in the treatment group then compared to the untreated control group. The measurement of the dose absorbed by the mouse in this study was carried out using dosimeters, and after 24 hours the treatment was given, it is then calculated the number of mouse leukocytes by using a hematology analyzer. Results: The results showed a decrease in blood in the first exposure group, which are platelets 713 x103sell / μL, leukocytes 7.61 × 103 / μL, hemoglobin 13.71 g / dL, and MCV 52.967 fl. The decrease in the 7-exposure group was platelets 699.5x103sell / μL, leukocytes 6.03 × 103 / μL, hemoglobin 12.81 g / dL, and MCV 52.167 fl. The decrease in the 10-exposure group was platelets 688,833 x103sell / μL, leukocytes 5,20 × 103 / μL, hemoglobin 12,06 g / dL, and MCV 51,483 fl. Thus, it can be concluded that the decrease in number that occurs in mouse is still within the normal limits. Keywords: periapical radiographs, platelets, leukocytes, hemoglobin, MCV