Women living in rural and urban areas of Mexico answered a questionnaire about what they were told at home about menstruation before their menarche (first menstruation), and answered the Beliefs About and Attitudes Toward Menstruation Questionnaire. Around half of both urban and rural women were told that they were going to experience negative perimenstrual changes. There were fewer urban than rural women who were advised to do or not to do certain activities while menstruating. Menstrual socialization affected the beliefs and attitudes concerning menstruation held by women as adults. These findings are discussed in light of the sociocultural background of the participants.