The controversy concerning the validity and reliability of generalized anxiety disorder (GAD) appears to be particularly relevant in the elderly, since physical symptoms associated with GAD can readily be considered as the consequences of normal aging. This study aims to analyze the structure invariance of a questionnaire assessing the DSM-IV diagnostic criteria across samples of older adults and college students. Ninety-seven adults aged 65 or over and 130 college students completed the Worry and Anxiety Questionnaire (WAQ). The results revealed that factorial invariance could be assumed and, in addition, that scores for severity of GAD symptoms were higher in younger subjects than in older ones. The results support the applicability of DSM-IV criteria for GAD in elderly people, as the factorial structure of the WAQ was the same for this age group as for younger adults. A higher degree of GAD severity was found in the younger sample.