Background: Previous research has suggested that clinical assessment of emotions in patients with cancer is suboptimal. However, it is a possibility that well-trained and experienced doctors and nurses do recognize emotions but that they do not evaluate all emotions as necessitating professional mental health care. This implies that the sensitivity of clinical assessment should be tested against the need for professional mental health care as reference standard, instead of emotional distress. We hypothesized that the observed sensitivity of clinical assessment of emotions would be higher when tested against need for professional mental health care as reference standard, compared with emotional distress as reference standard. Patients and Methods: A consecutive series of patients starting with chemotherapy were recruited during their routine clinical care, at a department of medical oncology. Clinical assessment of emotions by medical oncologists and nurses was derived from the patient file. Emotional distress and need for professional mental health care were assessed using the Distress Thermometer and Problem List. Results: Clinical assessment resulted in notes on emotions in 42.2% of the patient files with 36.2% of patients experiencing emotional distress and 10.8% expressing a need for professional mental health care (N = 185). As expected, the sensitivity of clinical assessment of emotions was higher with the reference standard “need for professional mental health care” compared with “emotional distress” (P '.001). For specificity, equivalent results were obtained with the two reference standards (P =.63). Conclusions: Clinical assessment of emotions in patients with cancer may be more accurate than previously concluded.