Objective: Standards for treatment of laryngeal clefts remain poorly defined. There are no large case series that report the efficacy of injection laryngoplasty (IL) in the treatment of pediatric Type 1 laryngeal clefts (LC-1). The objective of this study is to measure the effect of IL in young children with LC-1. Methods: A retrospective case series of 130 patients was completed over 3 years at a at a single institution included patients aged 1 month to 8 years, diagnosed with aspiration and penetration issues during swallowing based on a Videofluoroscopic Swallow Study (VFSS). Patients underwent surgical evaluation and intervention using carboxymethylcellulose gel injection. Collected data points included age in months at time of first injection, gender, race, pre- and post-operation VFSS scores, number of injections, co-morbidities and post-operative complications. VFSS scores were evaluated pre- and post-operatively to assess efficacy of intervention. A secondary outcome was efficacy in patients with aspiration compared to those with penetration alone. Results: This study included 77 male and 53 female patients. Sixty-two patients (48%) demonstrated a significant post-operative improvement in their swallowing function (P <.05). There were no statistical differences in age, number of injections, or the volume of the first injection. Patients that showed a post-operative improvement in swallowing function were on average 5 months older and had more severe aspiration and penetration compared to those who did not demonstrate a post-operative benefit and underwent less injections. The volume of injection did not appear to play a role in the success rate. Conclusion: Injecting the inter-arytenoid area in patients with LC-1 appears to confer some benefit to close to half of our patient population. Successful procedures seemed to occur in patients with more severe aspiration and penetration and older age.