Abstract Purpose To compare the clinical results of corticosteroid injection using landmark-guided injection (LMGI) and ultrasound-guided injection (USGI) techniques. Patients and methods We injected corticosteroids in 55 patients with extraarticular tennis elbow using LMGI and USGI techniques. All patients suffered from lateral elbow pain for more than 3 months with a tender point on the lateral epicondyle. This pain was exaggerated by wrist extension and specific physical activity. For postprocedural evaluation, in a randomized controlled assessor-blinded clinical trial, visual analog score (VAS), pain-free grip strength (PFGS), and the Nirschl staging system were assessed at 1, 6, 24 weeks, and 12 months. Results Only 48 participants were included in the final analysis (seven were excluded). Preoperatively, the average VAS scores, tenderness over lateral epicondyle, PFGS values, and Nirschl stages were almost the same (P=0.620, 0.505, 0.784, and 0.455). After 1 week of injection, there was no significant difference noticed in the VAS for pain at rest, tenderness during palpation, the PFGS and Nirschl stages between group 1 and group 2 (P=0.947, 0.724, 0.484, and 0.677, respectively). A statistically significant difference between the two groups was observed from 6 to 48 weeks. At the final follow-up, group 2 had a statistically significant better outcome when compared to group 1 (P<0.05). Conclusion USGI had a better long-term outcome than LMGI in the treatment of lateral epicondylitis.