The study was conducted to determine knowledge, attitude and practice towards Sexually Transmitted Diseases and HIV infections among communities in Biharamulo and Muleba districts, Kagera Tanzania. A total of 915 study participants were recruited and most of them (96.3%) knew that there are diseases which could be transmitted through sexual contact. Seventy one percent of participants thought STDs could be acquired through sharing a towel while fifty percent thought HIV could be transmitted through insect bites. Eighty five percent of school pupils who participated in the study reported to have been taught about AIDS and less than 30% on sex and pregnancy. Sixty three percent of study participants were of the opinion that a girl or woman should not refuse to have sex after being given a gift, and having sex with an elder partner was thought to be acceptable by almost fifty percent of participants. Over 50% percent of interviewees thought a girl or woman should not refuse to have sex with their friends. Although 99% of interviewees reported to have ever heard about condoms, only 28% reported to have ever used them irrespective of been affordable. Most schoolboys and about 50% of schoolgirls reported to have experienced sex by the time of the study. Thirty eight percent of girls reported to have first sex at the age of 14 years. Nine percent of the participants who reported to have experienced sex were forced to do so. Knowledge regarding STDs and HIV/AIDS was high among participants, but a sizeable proportion report misconception on transmission of STDs/HIV such as through sharing a towel and insect bites. Therefore it is recommended that S&RH intervention programme should address these misconceptions in order to match knowledge and practice, and achieve the intended objectives.