This study was carried out to determine the relationship between perceived spousal support and stress levels of mothers of children undergoing Bone Marrow Transplantation (BMT). The mothers of 150 children who were under treatment at the Istanbul Acıbadem Altunizade Hospital BMT Unit constituted the sample. Data were collected using the “Data Collection Form”, “Spousal Support Scale” and “Perceived Stress Scale”. Chi-square, Kolmogorov-Smirnov test, Independent t-test, and One Way Anova test were used to evaluate the data. Mothers' education, work, having another child and socioeconomic status, number of children, place of residence, family structure, consanguineous marriage, social security, presence of chronic disease, and having a chronic disease in a family member were for spousal support; Complications after BMT and the number of BMT performed were found to be predictive for stress level. As a result of the research, it was determined that as spouse support increased, mothers' stress levels continued to increase and their coping skills were stronger with spousal support.