Background: Depression and anxiety are common in patients with cancer. Aim: To adapt and validate the Hospital Anxiety and Depression Scale (HADS) for adult Chilean cancer patients, and to provide information about their prevalence of anxiety and depression. Material and methods: Two hundred fifteen patients with cancer answered an adapted version of HADS for Chilean population. The language adjustment of the scale was carried out with the opinions of 10 expert linguists and with a pilot study on 17 cancer patients. The Depression and Anxiety subscales of the DASS-21 were also applied to verify the convergent validity of HADS: Results: The confirmatory factor analysis indicated that the data fits the model of two correlated factors (anxiety and depression), Chi2 = 98.608; df = 76; p < .05; Chi2/df = 1.23, RMSEA = .037; CFI = .99; TLI = .98. Reliability analysis showed an adequate internal consistency of both subscales (0.76 for anxiety and 0.84 for depression) and the general scale (.87). Correlations between HADS and DASS-21 scores were significant for both anxiety (r =.514, p < .001) and depression (r =.600, p < .001). Prevalence rates were approximately 30% for depression (actual = 12%, possible = 22.8%) and approximately 20% for anxiety (actual = 7%, possible = 8.4%). Conclusions: We conclude that HADS is a reliable and valid instrument for screening clinically relevant anxiety and depression symptoms in Chilean cancer patients.