Background: The administration of intravenous (IV) acetaminophen is increasing worldwide, due to the higher costs of oral and rectal administration; hence, appropriate prescription of IV acetaminophen is highly important. The aim of this study was to check the compliance of injectable acetaminophen prescription based on the patient’s conditions with health protocols in the neurology ward of hospitalized adults in Hamadan, Iran. Methods: A total of 97 patients with the age range of 17-88 years hospitalized in the neurology ward of Shahid Beheshti hospital in Hamadan from April 2021 to September 2021, who received at least 1 dose of IV acetaminophen, were examined in this retrospective single-center cohort study. Demographic information and clinical parameters such as blood urea nitrogen, creatinine, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, international normalized ratio, the reason for administration, administration dose and intervals, and the number of administration doses with national guidelines underwent an investigation. The data of the study were extracted from the medical records of the patients and analyzed with SPSS software at a confidence level of 95%. Results: The results demonstrated that the indications for injecting acetaminophen were pain (62.9%), fever (32%), and simultaneous pain and fever (5.2%). The average dose of injectable acetaminophen, the duration of administration (minutes), and the administration intervals (hours) were 5.05±0.66, 67.50±6.62, and 12.34±5.37, respectively. The frequency of compliance with the instructions was 21.6% and 72.2% of non-compliance due to the lack of a need for an injectable form while there was the possibility of using an oral or rectal form. Conclusion: Based on the results of this study, the majority of IV acetaminophen in patients admitted to the neurology ward did not comply with national guidelines, and the most common cause of non-compliance was the use of the injectable form of acetaminophen. Moreover, improper administration of IV acetaminophen is not economically beneficial for the healthcare system.