The entire > or =65-year-old population living in a small Italian town, where alcohol use is almost ubiquitous, was assessed with a frequency-quantity questionnaire for alcohol intake and with two screening instruments for alcohol problems, the CAGE questionnaire and the MCV-gammaGT test. Aim of the study was to assess whether these instruments identify different subsets of subjects with alcohol problems. Of the 649 participants, 19.1% were at-risk drinkers (average intake > 40 g/day in men and > 20 g/day in women). Both the screening instruments were positive in only a minority of participants. Of the 377 drinkers, 53 gave > or =1 affirmative response to the CAGE questionnaire, whereas 24 had a positive MCV-gammaGT test. The concordance between positive CAGE questionnaire and MCV-gammaGT test was limited to seven subjects (kappa = 0.10), and these tests identified subjects who differed for several health and psychosocial characteristics. Participants aged > or =75 years drank less, but had similar prevalence of CAGE and MCV-gammaGT positive markers as compared to younger participants. In conclusion, excessive drinking is common in the elderly. Screening tests based on behavioral and biological markers identify two different sets of subjects with possible alcohol problems. This might indicate the opportunity to use these instruments in conjunction.