Approximately 30% of peruvian cancer patients experience clinically significant depressive symptoms, so it is recommended to screen patients for depression in all phases of the disease and treatment. Therefore, the evidence of validity of the scores of the peruvian version of the Patient Health Questionnaire (PHQ-9) for depression screening was evaluated in a population of 500 adult cancer patients from a specialized hospital in metropolitan Lima. Evidence of validity was found based on the content of the questionnaire (V> 0.8). A simple two-factor internal structure that explains 47% of the variance was identified. It presented an adequate goodness of fit (CFI=.942; TLI=.92; AGFI=.946; SRMR=.044; RMSEA=.058). The PHQ-9 and its Affective/Cognitive dimension showed adequate reliability (ω1=.76; ω2=.72), but moderate in the Somatic dimension (ω=.69). The instrument presents scalar measu...