Keselamatan pasien (patient safety) adalah suatu sistem dimana rumah sakit membuat asuhan pasien lebih nyaman. Hal ini termasuk assesment resiko, indentifikasi dan pengelolaan hal yang berhubungan dengan resiko pasien, pelaporan dan analisis insiden, kemampuan belajar dari insiden dan tindak lanjutnya serta implementasi  solusi  untuk meminimalkan  timbulnya  resikoWorld Health Organization (WHO) pada tahun 2011 mengumpulkan angka - angka penelitian rumah sakit di berbagai Negara antara lain Amerika, Inggris, Denmark, dan Australia, ditemukan kejadian tidak diharapkan (KTD)  dengan rentang 3,2 –16,6%. Data – data tersebut menjadikan pemicu berbagai negara segera melakukan penelitian dan mengembangkan sistem keselamatan pasien. Data di Indonesia tentang kejadian tidak diharapkan (KTD) apalagi  Kejadian  Nyaris Cedera (Near Miss)  masih langka,  namun dilain pihak terjadi  peningkatan tuduhan “mal praktekâ€, yang belum tentu sesuai dengan pembuktian akhir. Insidensi pelanggaran  patient safety (28,3%) dilakukan oleh perawat. Tujuan penelitian ini untuk mengetahui hubungan pengetahuan perawat tentang patient safety dengan tindakan pencegahan resiko jatuh pada pasien post operasi di RSUD Kota Semarang, penelitian ini menggunakan jenis penelitian kuantitatif dengan desain analitik kolerasi dengan rancangan penelitian cross sectional. Populasi dalam penelitian ini adalah semua perawat RSUD Kota Semarang berjumlah 330 dengan sampel 35 responden. Hasil penelitian ada hubungan pengetahuan perawat tentang patient safety dengan tindakan pencegahan resiko jatuh pada pasien post operasi di RSUD Kota Semarang. Kata Kunci : Pengetahuan Perawat,Patient Safety, Resiko Jatuh, Post Operation  RELATIONSHIP OF NURSE KNOWLEDGE AND PATIENT SAFETY PREVENTION OF FALL RISK IN PATIENTS POST OPERATION AT SEMARANG CITY HOSPITAL Abstract Patient safety is a system where hospitals make patient care more comfortable. This includes risk assessment, identification and management of matters relating to patient risk, incident reporting and analysis, the ability to learn from incidents and their follow-up and implementation of solutions to minimize risk. The World Health Organization (WHO) in 2011 compiled hospital research figures. in various countries including America, England, Denmark, and Australia, unexpected events (KTD) were found with a range of 3.2 – 16.6%. These data trigger various countries to immediately conduct research and develop patient safety systems. Data in Indonesia regarding unexpected events (KTD), especially near misses, are still scarce, but on the other hand there is an increase in accusations of "malpractice", which are not necessarily in accordance with the final evidence. The incidence of patient safety violations (28.3%) was carried out by nurses. The purpose of this study was to determine the relationship between nurses' knowledge about patient safety and prevention of falls in postoperative patients at the Semarang City Hospital, this study used a quantitative research type with a correlation analytic design with a cross sectional research design. The population in this study were all nurses at the Semarang City Hospital totaling 330 with a sample of 35 respondents. The results of the study showed that there was a relationship between nurses' knowledge about patient safety and preventive measures for the risk of falling in postoperative patients at the Semarang City Hospital. Keywords: Nurse Knowledge, Patient Safety, Fall Risk, Post Operation