Objective: This resarch considers the social and economical characteristics of streetwalker in Tehran in 2004. The purpose of this research is to determine the relationship between social and economical characteristics and becoming streetwalker of women . Method: The research Bulk of sample is 150 people, which is chosen by refering to a. Hajar of Crisis Intervention Center to tehran province (75 People) b. City surface and parks in Tehran in which 75 people are chosen. For the first case, the choise of bulk sample was complete, for the second one a random sampling was done with streetwalkers in city surface and parks during three month. The instrument for collecting in formation was questionnaire (involves 96 questions). The information was gathered by interviewing each of the samples. Findings & Result: The relation between social characteristics, economical characteristics, observation of streetwalkers in city surface and becoming streetwalker (as dependable variable) was meaningful.