Breast cancer is defined as the most common type of cancer that causes death among women (Siegel et al. 2019). It constitutes 24% of cancers and 15% of cancer-related deaths in women (T.R. Ministry of Health 2020). According to statistics made towards the end of 2020, there are 7.8 million women in the world who were diagnosed with breast cancer in the last 5 years and are alive. It is estimated that one in every 8 women will develop breast cancer in developed countries (WHO 2021).

The Ministry of Health reported the frequency of breast cancer in our country as 45.6/100,000 in women in 2018. The incidence of breast cancer is reported to be higher, especially in the 45-54 age range (TC Ministry of Health 2020).

Chemotherapy is one of the most frequently preferred treatment methods in the treatment of breast cancer and can cause serious side effects such as pain, nausea and vomiting, loss of appetite, shortness of breath, mouth sores, fatigue, insomnia, anxiety and depression, and may lead to a deterioration in the quality of life of patients (Waks and Winer 2019, Samami et al. 2021, Sajadian et al. 2017, McFarland et al. 2018, Hamer et al. 2017).

In the international and national literature, no study has been found comparing the effects of laughter and mindfulness therapy on the anxiety, depression, quality of life and spiritual well-being experienced by breast cancer patients. In this study, it is planned to investigate the effects of laughter and mindfulness therapy applications on the anxiety, depression, quality of life and spiritual well-being levels of women with breast cancer receiving chemotherapy.

Inclusion Criteria:

• Women who are 18 years of age or older, do not have communication problems, have and can use a smartphone, do not have internet problems to participate in group sessions, volunteer to participate in the study, receive chemotherapy at least once a month and will continue to receive chemotherapy during the study. Women with stage 1 and stage 2 breast cancer, women with primary and secondary education, women within the first year of treatment in terms of the number of cycles, women with a score of 8 or more on the Hospital anxiety and depression scale (0-7 points are normal, 8- A score of 10 is borderline, 11 and above indicates abnormality).

Exclusion Criteria:

• Women who did not meet the inclusion criteria, refused to participate in the study, and participated in less than 80% of the research practices (It is recommended to participate in at least 6 out of 8 sessions in the literature (Liu et al. 2022).),
• Women who use mindfulness therapy, laughter therapy or any complementary or integrative medicine in their daily lives outside the research, women who have a diagnosed psychological disease, metastasis or recurrence, and whose chemotherapy treatment was terminated before the study was completed,
• Women with stage 3 and stage 4 breast cancer, women who have been receiving chemotherapy for more than 1 year, women whose scores are 8 or below on the Hospital anxiety and depression scale (0-7 points indicate normal, 8-10 points indicate borderline, 11 and above indicate abnormality ).

Since breast cancer is a type of cancer more common in women, only patients diagnosed with female breast cancer were included.