Plebitis adalah salah satu komplikasi terapi infus. Salah satu faktor penyebab plebitis adalah kurang terampilnya perawat saat melakukan pemasangan infus. Tujuan penelitian adalah mengetahui hubungan pengetahuan perawat tentang terapi infus dengan kejadian plebitis dan kenyamanan. Jenis penelitian analitic-corelational dengan pendekatan cross-sectional, dengan jumlah sampel 65 perawat pelaksana rawat inap dan 65 pasien yang dipasang infus. Hasil menunjukkan 50,8% perawat memiliki pengetahuan kurang baik, angka kejadian plebitis sebesar 40%, dan 53,8% merasa nyaman dengan pemasangan infus. Ada hubungan yang signifikan antara pengetahuan perawat tentang terapi infus dengan kejadian plebitis (p= 0,000; α= 0,05), dan dengan kenyamanan (p= 0,000; α= 0,05). Direkomendasikan untuk perawat agar meningkatkan pengetahuan dan keterampilan pemasangan infus sehingga komplikasi dan ketidaknyamanan akibat pemasangan infus dapat dikurangi.Nursing?s Knowledge on Infusion Therapy Phlebitis is one of complications of infusion therapy Influence the Incidence of Phlebitis and Patients Comfort. The aspect that considered affecting the incidence of phlebitis and patient?s comfort is the nurses?skills on infusion therapy. This study aimed to determine the relationship between a nurse's knowledge on infusion therapy with the incidence of phlebitis and comfort. This was a correlation analytic with cross-sectional approach with the number of samples was 65 nurses who work in inpatients ward and 65 patients who received infusion. The results showed that 50.8% of respondents had have a poor knowledge, the incidence of phlebitis was 40%, and 53.8% felt of comfortable with the insertion of infusion canule. The results showed that there was a significant relationship between knowledge of nurses about infusion therapy with incidence of phlebitis (p= 0.000; α=0,05) and patients? comfort (p= 0.000, α=0.05). It is recommended that nurses have to improve knowledge and skills so that complications and discomfort caused by infusion might be prevented.