This experimental study, which was conducted to examine the necessity of aspiration procedure and its effect on pain in intramuscular (IM) injections made into the ventrogluteal site (VGS), is randomized controlled and double-blind. The patients in the study group ( n = 834) were assigned to the IM group with the aspiration period of 5 to 10 seconds (Implementation Group A-IGA), the aspiration period of 1 to 2 seconds (Control Group-CG), and no aspiration (Implementation Group B-IGB) according to stratified block randomization list. Patients’ pain levels were evaluated with the Visual Analog Scale (VAS). No bleeding was observed when aspiration periods of 1 to 2 and 5 to 10 seconds were followed during the injections administered to the VGS. The difference between the pain medians of patients in IGB and the CG were not significant ( p = .521). It can be said that there is no need to apply aspiration in IM applied into the VGS if the correct site is determined.