The present study aims to assess the effect of group reality therapy on depression and anxiety in breast cancer patients undergoing chemotherapy in Ali-Ibn-Abitalib hospital, Zahedan, in 2017-2018. The current study is an application of research using a semi-experimental design. It employs a pretest-posttest design and separates participants into control and experiment groups. Additionally, it is a qualitative study in terms of data collection.Beck’s depression and anxiety inventory (1998, 2000) was used to collect data. The statistical population of this study consists of all the breast cancer patients hospitalized in Ali-Ibn-Abitalib hospital, Zahedan. Non-probability available sampling was used to select the sample. The sample size consisted of 24 individuals randomly divided into two groups of experiment and control. The inclusion criteria were doctors’ diagnosis and depression and anxiety diagnosis based on the BDI and BAI. The experiment group received reality therapy in 10 90-minutes sessions, and the control group received no intervention. Data were analyzed using univariate covariance analysis. The results showed that group reality therapy leads to less depression and anxiety in breast cancer patients undergoing chemotherapy.