The proportion of geriatric depression recorded in Vietnam was 66.9%. Depression in older people is a risk factor for problems related to dementia, poor quality of life, and suicide. To have a good Vietnamese questionnaire for assessing geriatric depression, we conducted the study to translate and cross-culturally adapt the Geriatric Depression Scale-long-form with 30 items (GDS-30). The study has two steps. Step 1 is a translation of the GDS-30 scale. We followed the guideline by Beaton et al., (2000 & 2007). Firstly, two translators (informed and uninformed) translated the questionnaires. Secondly, the translations were synthesized. Thirdly, back translation was performed by two translators fluent in both Vietnamese and English but completely unknown of the original version of the scale and did not have medical expertise. Finally, seven experts reached a consensus on the pre-final Vietnamese version (GDS-30). Step 2 is a field test of the questionnaires on people 60 years or older. Then, we determined the internal consistency and test-retest reliability of the questionnaire in 55 Vietnamese inpatients in a geriatric department. Construct validity was determined by examining the relationship between depressive scores and patient characteristics. The Vietnamese version of GDS-30 was built with the agreement of all experts on the semantic, idiomatic, experiential, and conceptual equivalences between the original and pre-final Vietnamese versions of the GDS-30. The Cronbach’s alpha coefficient value was 0.928, indicating the items’ adequate internal consistency. Spearman’s correlation coefficient value of total scores between the first and second interviews showed medium correlation (0.479, < 0.001), and the stability is acceptable. The GDS-30 scale reached the construct validity because the proportion of geriatric depression according to GDS-30 was significantly different between characteristics groups, such as gender, employment, level of education, economic status, and sleep disturbance. The Vietnamese version of the GDS-30 scale had high consistency, satisfactory reliability, and understanding and can be used as a screening tool for depression in elderly patients in primary healthcare centers. This is the first depression rating scale for the elderly in Vietnam to be translated and validated. Non-psychiatric health professionals or patients can quickly self-assess and screen for the illness.