Hypospadias is a common congenital anomaly with a high incidence on postoperative complications. So, the purpose of the study was to investigate the effect of pre-designed instructions for mothers of children with hypospadias on postoperative complications. A convenient sample that consists of 60 mothers of children with hypospadias was included in the study. The sample was divided into 2 equal groups; the control group and the study group. Pre-post quasi experimental design was utilized to fulfill the aim of the study. The study was conducted in the pediatric surgical department and urology outpatient clinicat one Pediatric Hospital in Cairo. Three instruments were used to collect data about mothers' knowledge, mothers' practices regarding care of hypospadias, postoperative complications assessment sheet, and pre-designed instructions were provided for those mothers preoperatively. The study results revealed that a highly significant statistical difference was present between the control and the study group regarding mothers' knowledge in post-test. The majority of mothers in the control group and the study group had inadequate level of knowledge about hypospadias in pre-test. While more than two fifths of mothers in the study group had adequate level of knowledge in post-test. The results proved that the mothers' practices in post-test were increased more than in pre-test, less than half of the mothers in pre-test were not satisfied about performing diaper care correctly. However in post-test more than three quarters of mothers were performing this procedure correctly, and there were highly statistical significant difference between pre and post-test. Regarding early postoperative complications; the results demonstrated that more than two thirds of children in pre-test, compared to less than two fifth in post-test suffered from postoperative complications such as; infection, urinary tract obstruction and bleeding. The current study concluded that the pre-designed instructions for mothers of children with hypospadias were efficient by means of marked improvement of the knowledge and practices of the study group, which support the research hypotheses. So the results indicated that children with hypospadias were fewer early postoperative complications in the study group than the control group. The study recommended that pre-designed instructions must be provided for mothers of children with hypospadias to reduce postoperative complications. Also a longer follow-up could be necessary to monitor the late post-operative complications.