Plastibell is one of the most common disposable devices used for circumcision. The study aims to determine whether changing the thread type from cotton to polypropylene to tie around the Plastibell in neonatal circumcision would result in faster separation of the ring. Prospective, randomized, clinical and biomechanical studies were performed. All circumcisions were performed by a single surgeon. Data collected included anthropometric measures, demographic data, procedure time, complications, parent satisfaction, follow-up, and outcomes. The biomechanical study measured the tensile properties of both threads using a universal testing machine (4465; Instron, Norwood, MA). Two hundred full-term, male neonates aged between 24 and 48h were circumcised using Plastibell. Both groups were similar in gestational age, age at circumcision, body weight, height, head circumference, Apgar score at 1 and 5min, procedure time, Plastibell size, and parent satisfaction. The subjects were randomized into two groups of 100 neonates each: group I where Plastibell was tied by a cotton thread supplied by the manufacturerand group II where Plastibell was tied by Polypropylene 0. The mean duration for Plastibell fall-off was 8.98 days and 7.74 days in cotton thread and Polypropylene 0, respectively (P-value<0.001). There was no difference regarding the complications for both groups. The diameters of the cotton and Polypropylene 0 threads were 0.68mm and 0.35mm, respectively. The measured tensile strengths of cotton and Polypropylene thread were 180MPa and 457MPa, respectively. Plastibell tied by Polypropylene 0 fell off faster than that tied by cotton thread, with no significant differences in adverse effects or complications. This finding might be relevant for anxious parents and caregivers. Further studies are needed to examine other types and sizes of threads to investigate whether this separation period can be reduced further.