Chemotherapy is one of the cancer treatments by using  specific drugs to eleminate or reduce the cancer cells. Nurses who work to provide chemotherapy drugs must have  a good knowledge about the procedure in administering  the chemotherapy drugs, due to the cytotoxic effect which is hazardous towards the healthy body. The purpose of this study was to determined the level of knowledge of nurses about cytotoxic effects on the management of chemotherapy drugs. This study used a descriptive quantitative method with a total sample of 34 nurses. The sampling technique of this research was  purposive sampling. The data analysis technique was using the univariate analysis. Data collection was conducted in June 2019. The results showed 70,59% of nurses knowledge regarding cytotoxic effect was high, 29,41 % was moderate  and no nurses had less of knowledge about the cytotoxic effects of chemotherapy drugs. From the results of this study, it is strongly recommended for the hospital to develop their own training and activities such as workshops on managing the administration of chemotherapy for nurses working in the chemotherapy unit. It is also hoped that every nurse can increase their knowledge of the cytotoxic effects of chemotherapy drugs so that they can provide safe and appropriate chemotherapy services.