This study asks if the prevalence of loneliness in the population varies depending on the measures used, with special focus on loneliness among the elderly. The study compares loneliness in different age groups between 18 and 81 years old (N = 14,743) using two measures of loneliness: the (indirect) six-item De Jong Gierveld Loneliness Scale and a single-item, direct question about loneliness. Data are from the Norwegian LOGG (Life Course, Generation, and Gender) study. We compare the findings on loneliness according to age, gender, health, and partner status. Overall, the two loneliness measures indicate a similar prevalence of loneliness, but attribute loneliness to somewhat different people. When using a direct measure, loneliness is more prevalent among women; when using the (indirect) De Jong Gierveld Scale, loneliness is more prevalent among men. Also, the association between age and loneliness differed when using the direct and the indirect measure.