We analyzed the sexual behavior and sexually transmitted diseases (STDs) of street-based female sex workers (SFSWs) of Rajshahi city and examined their socio-demographic profiles. Among the SFSWs attending three drop-in centers (DIC) named PIACT, PROVA, and Suraksha Madhumita in Rajshahi, 150 self-motivated and willing individuals were interviewed through a structured questionnaire to obtain obstetric histories and socio-demographic information. Among these SFSWs, 56.7% were infected with two or more pathogens of STDs, with gonorrhea, chlamydia, herpes, syphilis, and trichomoniasis observed in 23.3, 27.3, 24.0, 17.3, and 20.0%, respectively. We found a strong association between the prevalence of STDs among SFSWs and their socio-demographic profiles. Illiterate and comparatively older SFSWs who spent very little money for health purposes, had larger numbers of children, and used condoms inconsistently were observed to be at higher risk of STDs. These results observed with bivariate analysis were also confirmed by logistic regression analysis.