Purpose. To assess the diagnostic practice patterns of physical therapists (PTs) and compare the diagnostic classification and label that PTs use to direct treatment to the pathologic diagnostic label used by physicians for patients with an oncology diagnosis. Background . A topic of great interest among health care providers who examine and diagnose patients is the challenge of accurately and reliably classifying patients into diagnostic groups for management. PTs direct their diagnosis toward identifying the movement system impairments and activity limitations resulting from cellular and systemic pathology and focus their interest at the tissue, organ and person level. Thus we can say that a physical therapy (PT) diagnosis labels movement related impairments producing activity and participation limitations rather than the disease. In order to have a common language of diagnosis for the diagnostic categories used by the PTs, The Guide to Physical Therapist Practice provides lengthy labels associated with the preferred practice patterns and describes the tests and measures used to identify the patients who belong in each diagnostic group. These are very broad patterns that set the boundaries for 80% of the patients who could be categorized into the group. Each group is associated with many pathologic diagnoses, (ICD9 Codes). In the acute care setting, PTs often manage patients with multiple pathologies or pathology that produces multiple impairments. Pathology such as Neoplasm (benign or malignant) may affect various systems of body. Patients with primary pathology such as neoplasm often have multi-system impairments that cannot be simply or easily grouped into a single movement related diagnostic pattern. Therefore, these patients represent an opportunity for PTs to demonstrate the difference between a pathology diagnosis that directs medical intervention and an impairment diagnosis that directs PT intervention. Method. Data were retrospectively collected from 100 randomly selected inpatient charts for patients with primary diagnosis of neoplasm, at Massachusetts General Hospital, Boston, MA. Descriptive statistics, frequency count and grouping of variables were used to identify the diagnostic practice patterns used and to differentiate between a pathology diagnosis and an impairment diagnosis. Results. Thirty-two different types of malignancies provided data for 100 inpatient charts. Patients were categorized by PTs into 14 different practice patterns. Of these, the majority fell into five practice patterns, namely pattern 5E (26%), pattern 6B (18%), pattern 5D (17%), pattern 5A (14%) and pattern 4I (9%). Of these, 96% of patients received PT interventions which included therapeutic exercise as the main intervention, along with home management comprising 92% of interventional strategies. Conclusion . In this population, all patients were diagnosed and classified by the PTs. There was a difference in the diagnostic classification between the pathology diagnosis and the diagnosis made by the PTs for these patients who have a primary pathology producing multi-system impairments. Additionally, these patients were not categorized by PTs into a single preferred practice pattern, but into a variety of preferred practice patterns that appear to be based on their movement-related impairments and activity limitations.