Introduction: Parental knowledge on nephrotic syndrome and disease relapse is important for early recognition and treatment of relapse to prevent the complications. Parental knowledge on nephrotic syndrome was reported to be inadequate from published studies. To date, there is no study on parental knowledge on childhood nephrotic syndrome in Malaysia. This study is thus aimed at to determine the level of knowledge on NS and disease relapse among parents of children with nephrotic syndrome and determine factors that influence knowledge on nephrotic syndrome and disease relapse. Study Design and Methods: This was a cross-sectional study conducted in Paediatric Nephrology Clinic, Hospital Selayang from November 2016 to November 2017. Seventy-eight parents were recruited based on universal sampling. Selfadministered questionnaire in Bahasa Malaysia and English was designed through focus group discussion with five subject matter experts and validated through content validity. Data was analysed using IBM SPSS Statistics 23.0. Results: Majority of parents or guardians (91%) were able to answer more than 50% of the questions correctly. Of these, 56% were able to answer more than 75% of the questions correctly. A 'cut-off' of 75% was defined as good knowledge. Parents of children with frequent relapses had higher parental knowledge and this was statistically significant (p=0.025). Conclusion: Parental knowledge on nephrotic syndrome and disease relapse was still inadequate as only 56% parents had good knowledge. The main areas of deficit in parental knowledge were related to medications, infections, home urine dipstick monitoring, and recognition of warning signs during relapse.