[Penelitian bertujuan mengetahui kepadatan hunian, aktivitas seksual orang tua dan efeknya terhadap perilaku seksual remaja di Yogyakarta tahun 2015. Penelitian ini menggunakan desain cross sectional, analisis regresi logistik. Hasil penelitian ini menunjukkan bahwa orang tua yang tinggal di hunian padat mempunyai resiko 2 kali lebih tinggi untuk melakukan aktivitas seksual yang berdampak negatif bagi anaknya dibanding orang tua yang tinggal di hunian yang tidak padat (OR 2,0695% CI: 1,030-3,723). Remaja yang tinggal di hunian padat mempunyai resiko 1,7 kali untuk melakukan perilaku seksual beresiko dibanding remaja yang tinggal di hunian yang tidak padat (OR 1,78 95% CI:0,63-5,00). Faktor yang mempengaruhi perilaku seksual remaja adalah jenis kelamin, sikap, media informasi dan peran teman sebaya. Saran Bagi Dinas Kesehatan dan puskesmas setempat program program penyuluhan remaja PKPR dan melatih konselor teman sebaya (Peer Group) sebaiknya juga dilakukan di daerah dengan kepadatanhunian tinggi;The study aims to know residential density, sexual activity of parents and its effect on sexual behaviour among teenagers in Yogyakarta in 2015. The study uses cross sectional design with regression logistic analysis. The result shows that the parents who live in dense residents have risk two times higher to do sexual activity that has bad effect on the children than the parents who live in otherresidents (OR 2,06 95% CI: 1,030-3,723) while the teenagers who live in dense residents has risk 1.7 times higher to do risked sexual activity than the teenagers who live in other place (OR 1,78 95% CI:0,63-5,00). Moreover, the factors of sexual activity among teenagers are sex, attitude, media and the role of peer group. The suggestion for health department and community health centre in the area is doing a campaign forteenagers and training in risked area i.e. urban area,especially area that has high number of population, The study aims to know residential density, sexual activity of parents and itseffect on sexual behaviour among teenagers in Yogyakarta in 2015. The studyuses cross sectional design with regression logistic analysis. The result shows thatthe parents who live in dense residents have risk two times higher to do sexualactivity that has bad effect on the children than the parents who live in otherresidents (OR 2,06 95% CI: 1,030-3,723) while the teenagers who live in denseresidents has risk 1.7 times higher to do risked sexual activity than the teenagerswho live in other place (OR 1,78 95% CI:0,63-5,00). Moreover, the factors ofsexual activity among teenagers are sex, attitude, media and the role of peergroup. The suggestion for health department and community health centre in thearea is doing a campaign forteenagers and training in risked area i.e. urban area,especially area that has high number of population]