This experiment was designed to examine the ability of older and younger adults to remember the source of information. Three types of source monitoring tasks were investigated: discriminating between externally derived and internally generated memories, discriminating between two types of internally generated memories, and discriminating between two types of externally derived memories. Relative to younger adults, older adults had more difficulty discriminating between memories of the same class (external-external and internal-internal), but they did not have more difficulty discriminating between memories of different classes (external-internal). These findings indicate that the age-related difficulty in remembering the source of information should not be characterized as a general deficit. Factors that may account for age deficits in source monitoring are discussed drawing upon the Johnson-Raye (1981) reality monitoring framework.