Background and Objective: Intramuscular (IM) injections are administered to patients in all health care settings. Even though this procedure is invasive and the evidence supporting the process of administration is extensive, techniques and procedures vary throughout the literature and in practice. The purpose of this descriptive correlational study was to 1) investigate the literature on current evidence-based IM injection procedures pertaining to gender, patient weight, injection site, needle length, and technique, 2) compare surveyed healthcare personnel self-reported IM injection practices, and 3) query respondents on informational resources they access, continuing education they receive, and their years of healthcare experience and higher education. Methods: The Intramuscular Injection Questionnaire (IIQ) was sent via email to various professional healthcare facilities and their respective social media sites. Two hundred and six (206) healthcare personnel of various healthcare backgrounds and educational levels accessed the IIQ via a link to Qualtrics software. SPSS Version 24 was used for data analysis. Results: Most respondents were registered nurses with 4 -15+ years of experience. Seventy-eight percent of respondents considered their IM injection knowledge at above average or expert levels. Gender was not considered an important factor when selecting an injection needle among 75% of participants. Of all respondents, 61% use z-track technique, 59% use the ventrogluteal site and 34% always bunch or stretch the skin during injection. IM injection education was not provided in 75% of healthcare facilities. Conclusions: IM injection practices vary among respondents and in the literature; some reported practices are contrary to current evidence-based practice. While the evidence provides some sound recommendations, some procedures are not well-documented or supported including in nursing texts. Nurses and other healthcare personnel must critically analyze the site, depth, needle, volume, medication, vaccine, and whether to bunch or stretch, according to evidence-based practice. Healthcare facilities should provide IM injection education routinely to ensure safe practices. Future studies (Level 1 and 2) are needed to further demonstrate the best evidence leading to safe and effective IM injections.