OBJECTIVES:  we aimed to assess adequacy of cancer pain treatment, its subsequent interference on functioning and the associated factors in the oncology ward of Gondar University Hospital(GUH). METHODS:  This is a cross-sectional study conducted from February 15 to May 15, 2016 in the oncology ward of GUH. A questionnaire-based interview using Brief Pain Inventory-Short form (BPI-sf) and chart review were used as data collection procedures. RESULTS:  Of 83 patients, 76 (91.6%) cancer patients experienced pain with varying degree of severity. Fifty four (65%) patients were receiving inadequate cancer pain treatment with negative PMI. Of 76 cancer patients with pain, 68(89.2%) experienced pain interference with their daily activities. Educational level, metastasis status, number and types of analgesics for adequacy of cancer pain management, where as stage of tumor, presence of metastasis, history of treatment modality, history of pain and pain management adequacy for pain interference on patient’s daily functioning were identified as statistically significant predicting factors. CONCLUSIONS: It is vital to anticipate and assess pain of the cancer patients as routine clinical practice to optimize analgesic therapy through identifying and intervening barriers of adequacy of pain management, thereby improving patient health outcome and quality of life.