Background: Mindfulness-based program incorporating meditation practices and self-efficacy are gaining popularity among cancer patients. The current study aimed to evaluate the effects of a mindfulness-based program and perceived self-efficacy for patients with lung cancer. Methods: A quasi-experimental study was conducted in the outpatient clinics and nuclear medicine clinic at the New Cancer Institute at Menoufia University, Shebien Elkom City, Egypt. A purposive sample of 160 patients with lung cancer was enrolled, from whom data were collected through 5 tools: Tool (1): Structured interview questionnaire including demographic and medical data, Tool (2): Condensed Memorial Symptom Assessment Scale (pre/post), Tool (3): Eastern Cooperative Oncology Group Performance Status (pre/post), Tool (4): Self-Efficacy Pulmonary Rehabilitation Adapted Index (pre/post) and Tool (5): Questionnaire about mindfulness which includes knowledge, reported practice and five-facet mindfulness (pre/post). Results: This study displayed statistically significant improvements in symptoms (5.65 ± 1.33 to 3.00 ± 1.36), performance status (1.75 ± .83 to 2.25 ± .86), mindfulness (18.62 ± 2.32 to 29.75 ± 4.06), breathing meditation (1.17 ± 1.64 to 5.70 ± 1.60), self-efficacy (20.37 ± 2.93 to 33.32 ± 5.11), and knowledge (1.65 ± 2.36 to 13.17 ± 2.004) for patients with lung cancer after program application. Conclusion: Implementation of a mindfulness-based program and perceived self-efficacy have positive effects on improving physical and psychological symptoms, breathing meditation practice, performance status, and knowledge among lung cancer patients.