Background There is a growing interest in the use of biologic agents such as platelet-rich plasma and mesenchymal stem/stromal cells to treat musculoskeletal injuries, including meniscal tears. Although previous research has documented the role of diagnostic ultrasound to evaluate meniscal tears, sonographically guided (SG) techniques to specifically deliver therapeutic agents into the meniscus have not been described. Objective To describe and validate SG injection techniques for the body and posterior horn of the medial and lateral meniscus. Design Prospective, cadaveric laboratory investigation. Setting Academic institution procedural skills laboratory. Subjects Five unenbalmed cadaveric knee-ankle-foot specimens from 5 donors (3 female and 2 male) ages 33-92 years (mean age 74 years) with body mass indices of 21.1-32.4 kg/m 2 (mean 24.1 kg/m 2 ). Methods A single, experienced operator completed SG injections into the bodies and posterior horns of the medial and lateral menisci of 5 unenbalmed cadaveric knees using colored latex and a 22-gauge, 38-mm needle. After injection, coinvestigators dissected each specimen to assess latex distribution within the menisci and identify injury to intra-articular and periarticular structures. Main Outcome Measures Latex location within the target region of meniscus (accurate/inaccurate), and iatrogenic injury to "at risk" intra- and periarticular structures (present/absent). Results Seventeen of 20 injections were accurate. Two of 3 inaccurate injections infiltrated the posterior horn of the medial meniscus instead of the targeted meniscal body. One inaccurate lateral meniscus injection did not contain latex despite sonographically accurate needle placement. No specimen exhibited injury to regional neurovascular structures or intra-articular hyaline cartilage. Conclusions SG meniscus injections are feasible and can accurately and safely deliver injectates such as regenerative agents into bodies and posterior horns of the medial and lateral menisci. The role of SG intrameniscal injections in the treatment of patients with degenerative and traumatic meniscal disorders warrants further exploration. Level of Evidence Not applicable.