The purpose of this cross-sectional, correlational study was to describe stomatitis-related pain in women with breast cancer undergoing autologous hematopoietic stem cell transplant. The hypotheses that significant, positive relationships would exist between oral pain and stomatitis, state anxiety, depression, and alteration in swallowing were tested. Stomatitis, sensory dimension of oral pain, and state anxiety were hypothesized to most accurately predict oral pain overall intensity. Thirty-two women were recruited at 2 East Coast comprehensive cancer centers. Data were collected on bone marrow transplantation day +7 ± 24 hours using Painometer, Oral Mucositis Index-20, Oral Assessment Guide, State-Trait Anxiety Inventory, and Beck Depression Inventory. Data analysis included descriptive statistics, correlations, and stepwise multiple regression. All participants had stomatitis; 47% had oral pain, with a subset reporting continuous moderate to severe oral pain despite pain management algorithms. Significant, positive associations were seen between oral pain, stomatitis, and alteration in swallowing and between oral pain with swallowing and alteration in swallowing. Oral pain was not significantly correlated with state anxiety and depression. Oral sensory and affective pain intensity most accurately predicted oral pain overall intensity. Future research needs to explore factors that affect perception and response to stomatitis-related oropharyngeal pain and individual patient response to opioid treatment.