Background & Aim: Phenylketonuria (PKU) occurs due to congenital disorder in phenylalanine metabolism, and leads to progressive mental retardation. Beginning a diet can prevent the complications of the disease. The purpose of this study has been to investigate the effect of parents’ knowledge on control of  serum phenylalanine value in children with PKU.

Materials & Methods: The current descriptive-analytical study, was  conducted on 45 Subjects(1-18 years) with their parents who were selected out of the 65 patiens with PKU reffered to Abuzar Hospital in the Ahvaz province in 2013. The extent of the parents’ knowledge was investigated with a researcher-made questionnaire including demographic and diet information, and the children’s serum phenylalanine was assessed and recorded using venous blood samples in all the families. SPSS 21 software was used for data analysis.

Results: ANOVA test did not show a significant relationship between the knowledge of families and serum phenylalanine level of children (p>0.05). also, chi-square test did not show a significant relationship between the serum phenylalanine level of children and demographic variables, parental age, education, income, place of residence, age at diagnosis, previous training parents (p>0.05).

Conclusion: The present study demonstrates that parents do not have adequate information on the disease and control  of their children’s serum phenylalanine value; therefore, it is essential to hold training workshops in order to the increasing  patiens  parents information in the respective centers.