Background: Management of positional plagiocephaly by wearing a cranial molding helmet has become a matter of growing medical interest. Some research studies reported that starting helmet therapy early (age 5 to 6 months) is important and leads to a significantly better outcome in a shorter treatment time. The aim of the present study was to evaluate the effectiveness of cranial remodeling treatment with wearing helmet for older infants (${geq}18$ months). Methods: We conducted a retrospective study of 27 infants with positional plagiocephaly without synostosis, who were started from 2008 to 2012. Every child underwent a computerized tomography (CT) before starting helmet therapy to exclude synostosis of the cranial sutures and had CT performed once again after satisfactory completion of therapy. Anthropometric measurements were taken on using spreading calipers in every child. The treatment effect was compared using cranial vault asymmetry (CVA) and the cranial vault asymmetry index (CVAI), which were obtained from diagonal measurements before and after therapy. Results: The discrepancy of CVA and CVAI of all the patients significantly decreased after cranial molding helmet treatment in older infants (${geq}18$ months) 7.6 mm from 15.6 mm to 8 mm and 4.51% from 9.42% to 4.91%. Six patients had confirmed successful outcome, and all subjects were good compliance patients. The treatment lasted an average of 16.4 months, was well tolerated, and had no complication. Additionally, the rate of the successful treatment (final CVA ${leq}5mm$) significantly decreased when the wearing time per was shorter. Conclusion: This study showed that treatment by cranial remodeling orthosis was effective if the patient could wear the helmet longer and treatment duration was somewhat longer than in younger patients, well tolerated in older infants and had no morbidity. This therapeutic option is available and indicated in these older infants before other cranial remodeling surgery.