Objective. To assess the effectiveness of intra-articular triamcinolone injection and physiotherapy singly or combined in the treatment of adhesive capsulitis of the shoulder. Methods. Eighty patients with adhesive capsulitis of less than 6 months duration were randomized to one of four groups: Group A, injection of triamcinolone 20 mg and eight sessions of standardized physiotherapy; Group B, injection of triamcinolone 20 mg alone; Group C, placebo injection and eight sessions of standardized physiotherapy; or Group D, placebo injection alone. All subjects were given an identical home exercise programme. Outcome measures were assessed at 6 weeks and 16 weeks. The primary outcome measure was Shoulder Disability Questionnaire (SDQ) score. Secondary outcomes were measurement of pain using a visual analogue scale (VAS), global disability using VAS and range of passive external rotation. A two-way analysis of variance was used to explore the effects of corticosteroid injection and physiotherapy. Results. At 6 weeks, the SDQ had improved significantly more in the groups receiving corticosteroid injection (P = 0.004). Physiotherapy improved passive external rotation at 6 weeks (P = 0.02) and corticosteroid injection improved self-assessment of global disability at 6 weeks (P = 0.04). There was no interaction effect between injection and physiotherapy. At 16 weeks, all groups had improved to a similar degree with respect to all outcome measures. Conclusion. Corticosteroid injection is effective in improving shoulder-related disability, and physiotherapy is effective in improving the range of movement in external rotation 6 weeks after treatment.