Background: Periarthritis shoulder is a common cause of chronic shoulder pain. Conventionally, Intraarticular Platelet Rich Plasma (PRP) injection has been used for its treatment. Rotator cuff interval is involved in pathogenesis of adhesive capsulitis, so PRP injection at rotator interval can become an alternative to conventional intra-articular approach. Aims: This randomised controlled trial was done to comparethe efficacy of PRP injection by intra-articular and rotator interval methods for management of periarthritis shoulder. Methods: The study was carried out by randomising 60 patients, aged>18 years into two groups; group A (n=30, intraarticular) and group B (n=30, rotator interval). They were given 3-4 ml of freshly prepared PRP intra-articularly and at rotator interval under ultrasound guidance. The Shoulder Pain and Disability Index (SPADI), Numerical Rating Scale (NRS) score and post injection complications were assessed at 0, 1st and 3rd month in both the groups. Results: The median NRS and SPADI scores were equivalent in both the groups at baseline. At 1st and 3rd month post injection, the median SPADI and NRS scores in group B were significantly lower than group A(p<0.05). There were no reported complications from both the groups. Conclusion: Both intra-articular and rotator interval methods of PRP injection were efficacious in pain reduction as well as in improving the shoulder functions, but rotator interval approach was more effective than intra-articular for management of periarthritis shoulder.