Background: One of the most dangerous illnesses affecting women's physical, mental, and social well-being is breast cancer. A mastectomy alters a woman's daily existence and has a detrimental impact on her perception of own body. The objective of the study was to evaluate the effect of counseling program on improving body image and feeling of loneliness among post-mastectomy women attending clinical oncology outpatient clinic at Zagazig University Hospital. Method: An interventional study was conducted among post-mastectomy women. Participants were randomly allocated to counseling and control groups. Participants were evaluated by the body image after breast cancer questionnaire (BIBCQ) and cancer loneliness scale (CLS) before and after implementation of six consecutive counseling sessions. Results: A total 116 women were included; 58 in intervention group and 58 in control group. The mean age was 45.67±8.98 and 48.1±7.59 years, respectively. After implementation of the intervention, all domains of body image significantly decreased compared to baseline in the intervention group with exception of body concern. On the other hand, vulnerability, limitations, and body concerns significantly decreased compared to baseline in the control group. For the overall score, all patients frequently reported experiencing negative thoughts about cancer and feelings of loneliness. However, after the intervention, the intervention group showed a significant increase in the frequency of infrequent perception of bad thoughts compared with the control group (77.6% vs. 37.8%, p<0.001). Conclusions: Counseling program had a positive effect on improving accepting body image and feeling of loneliness among women with breast cancer.