PURPOSE/HYPOTHESIS: The purposes of this pilot study were to (1) describe the prevalence of clinical signs and symptoms of breast cancer–related lymphedema (BCRL) and upper extremity function for long-term breast cancer survivors (BCSs); and (2) evaluate associations between BCRL signs, symptoms, diagnosis, and function among long-term BCSs. BACKGROUND: BCRL prevalence varies widely—anywhere from 0% to 65% depending on the type of surgery, measurement method, lymph node resection, and number of intent-to-cure medical modalities. BCRL signs, symptoms, and functional impairment are used to diagnose BCRL. The majority of cancer survivors are older than 65 years, and survival rates of BCSs are the highest in history. Therefore, we focus our study on long-term BCS. NUMBER OF SUBJECTS: 577 BCSs. MATERIALS/METHODS: We contacted 1200 BCSs previously enrolled in epidemiologic studies for this cross-sectional, observational study. We used computer-assisted telephone interviews and queried participants using binary variables (1 = yes; 0 = no) about breast cancer–related edema/pitting edema, skin texture, hemosiderin staining, and physician diagnosis of BCRL. We measured upper extremity function using the Shoulder Pain and Disability Index (SPADI). We analyzed our data with descriptive statistics (frequencies, mean, median, mode, standard deviation). We compared SPADI means by each BCRL sign, symptom, and diagnosis with t tests (P < .05). All data were analyzed using SAS. Northeastern University Internal Review Board approved this study. RESULTS: We recruited 577 BCSs and, on average, participants were 56 years old, completed high school, survived more than 12 years since diagnosis, 42% were African American, and the remainder were white/Caucasian. One hundred sixty-one participants reported at least 1 BCRL signs and symptoms. Each sign/symptom was significantly associated with shoulder dysfunction (P < .0001). However, signs/symptoms and shoulder dysfunction were not statistically associated with physician-diagnosed BCRL. CONCLUSIONS: Our data suggest that BCRL signs and symptoms—including upper extremity dysfunction—may not be associated with a diagnosis of BCRL by physicians. It may be that BCSs are underreporting signs, symptoms, and functional impairments and contributing to patient, physician, and health system barriers to care for long-term BCSs. The diagnosis of BCRL appears to be random despite signs, symptoms, and upper extremity dysfunction indicative of BCRL. CLINICAL RELEVANCE: It appears that serious unmet needs exist regarding BCRL detection and diagnosis for long-term BCSs. Our research holds implications for rehabilitation services utilization for those with BCRL.