Summary The following were investigated in a series of studies on 366 college students: (a) individual differences associated with horoscope reading habits, (b) the reliability and validity of daily and monthly horoscope forecasts and astrologically based personality descriptions, and (c) the effects of knowing the zodiac sign on the perception of the usefulness of horoscope forecasts and on the accuracy of astrologically based personality descriptions. Results indicate that females were more likely to read their horoscopes. Although locus of control was unrelated to horoscope reading habits, Neuroticism on the EPI was closely related. Daily and monthly forecasts were shown to be unreliable and invalid. Astrologically based personality descriptions were found to have some reliability. Knowledge of zodiac sign was found to affect ratings of horoscope usefulness and accuracy of astrologically based personality descriptions. Such personality descriptions, even when not identified by zodiac sign, were shown to have some validity, at least in the eyes of readers. These results are explained by familiarity effects and by the “Barnum effect.”