Background and objectives : Cranioplasty following cranioplasty is historically considered as a cosmetic surgery. Until recent times, little was known regarding the therapeutic effects of cranioplasty. The purpose of this study was to evaluate the effect of cranioplasty on neurological outcome in the patients with decompressive craniectomy. Our objective was to assess the neurological outcome of cranioplasty based on various scoring systems including BI(Barthel index), FIM(Functional independence measurement) ,GCS (Glasgow come score) and extended Glasgow outcome score(GOS) Methods : We conducted a prospective hospital based observational cohort study at Department of neurosurgery, Government medical college, Kozhikode after obtaining ethical committee clearance from the instituitional Ethics committee. Patients above 18 years who had underwent decompressive craniectomy admitted for cranioplasty were enrolled in to this study from August 2019 to July 2020 and were followed up for next 6 months for any complications. Glasgow coma scale, extended Glasgow outcome score , Barthel Index, Functional independence measurements – Total , Motor and cognitive scores were recorded pre-operatively , 1 day prior to surgery. Postoperative scores were also recorded after 1 month and 3 months . The details were collected in the proforma, was entered in to masterchart and analysed. Results and Discussion : A total of 58 patients were enrolled in to this study. Of these, 20.7% (n=12) were females and 79.3%(n=46) were males. Mean age of the patients in our study was 41.21 years (SD-12.97 years).Most common indication for decompressive craniectomy was acute SDH (62.1%) . Mean Preoperative GCS in our study group was 14.69 (SD -1.245), while the mean postoperative GCS at 1 month and 6 months were 14.71 and 14.76 and the difference were not statistically significant. Average time duration between decompressive craniectomy and cranioplasty cranioplasty varied from 4 months to 23 months with a mean duration of 7.65 months. Pre-operative mean extended Glasgow outcome score (GOS-E) was 7.41 (SD=0.94) and the mean postoperative GOSE at 1 month and 6 months were 7.69 and 7.71 and the difference was statistically significant.(p<0.001). Mean Preoperative functional independence measurement – motor (FIM-M) score was 75.5 (SD=14.74) Mean postoperative FIM-M at 1 month and 6 months were 84.71 and 84.98 . Similarly, mean Preoperative FIM cognitivescore 30.98 (SD 5.46)M, while the corresponding postoperative values at 1 month and 6 months were 32.66 and 32.97. Hence, mean FIM-Total score was 114.52(SD = 20.2), while the mean postoperative FIM-Total at 1 month and 6 months were 117.36 and 117.9. The difference in FIM-M, FIM-C and FIM-Total scores and 1 month and 6 months compared to the preoperative scores were statistically significant (p<0.001). Complication rate in our study was 17.2 % , which included postoperative collection, hydrocephalus, seizures and surgical site infection. There was no significant difference in the complication rates in the patients with the early and late cranioplasty. Conclusion: Cranioplasty following decompressive craniectomy is not only cosmetic , but also therapeutic. Cranioplasty improved the neurological outcome in the patients with cranioplasty , which was indicated by the statistically significant improvement in extended Glasgow outcome score ,Functional independence measurement – Total score, motor subtotal score and cognitive subtotal scores at 1 month and 6 months. However our study did not show any statistically significant improvement in the Glasgow coma scale at 1 month or 6 months. No statistically significant difference in neurological outcome was noted in patients with early and late cranioplasty. Complication following cranioplasty included postoperative collection, hydrocephalus, seizures and surgical site infection.