Social isolation and loneliness are often considered to be important and frequent problems in old age. However, the empirical support for this notion is weak. Results from Swedish studies show that rather extensive social networks continue into old age. Only a small minority can be said to be isolated and suffering from feelings of loneliness. This minority, however, reports a lower life satisfaction, which can also produce physical and psychological problems. Increased attention must be directed toward such negative consequences of weak social networks. This is especially important in discussions of how to alter a social situation characterized by loneliness and isolation. It is emphasized that further research within this field must be based on more explicit theories.