Introduction: Acute pain is frequent among patients visiting the emergency department (ED). In addition to the acute discomfort, pain has been linked to adverse events and poorest outcomes in older adults. However, pain is frequently overlooked by emergency clinicians, particularly in older adults. Advanced age has been linked to poor recognition and under treatment of pain. The contribution of ED investigations and procedures to the patient's pain is unknown. This study aims to determine the intensity of the pain induced by the investigations and procedures commonly performed in the ED. Methods: In two EDs, a convenience sample of older adults (≥ 65 years old) with at least two investigations or procedures performed during their ED visit were eligible. Patients were excluded if they were hemodynamically unstable, in palliative care or not oriented in time and space. The pain intensity was assessed at bedside by a research assistant for the following investigations or procedures: blood sampling, intravenous catheter, electrocardiogram, X-rays, computed tomography, beside ultrasound, urinary catheter, cervical collar and prehospital immobilization mattress. The predetermined sample size was 50 pain assessment per investigation or procedure. The pain intensity was assessed using a numerous rating scale (NRS) ranging from 0 (no pain) to 10 (most severe pain), for each investigation or procedure received. NRS results are presented using median (med) and interquartile range (IQR) and classified as followed: no pain (0), mild pain (1-3), moderate pain (4-6) and severe pain (7-10). Results: Between June 2018 and December 2019, 494 patients were screened of which 318 were finally included (exclusion: not oriented (n = 113), refusal (n = 27), palliative care (n = 34), other reasons (n = 12)). The mean age of included patients was 77.8 years old (standard deviation = 8.0), 54.4% were female and 78.6% were living in the community. Only 15 patients (4.7%) were known to have cognitive impairment or dementia and 23 patients (7.2%) were on regular or PRN opioid medication at home. The expected sample size of at least 50 pain score assessment per investigation or procedure was obtained for all interventions with the exception of urinary catheter (n = 23) and immobilization mattress (n = 35). For the other investigations or procedures, the number of pain assessment ranged between 51 (cervical collar) and 231 (blood sampling). All investigations and procedures were associated with a median pain score of 0 with the exception of blood sampling (n = 231, med NRS 1 (IQR 0;3)), intravenous catheter (n = 241, med NRS 1 (IQR 0;4)), urinary catheter (n = 23, med NRS 4 (IQR 1;6)), cervical collar (n = 51, med NRS 5 (IQR 0;8)) immobilisation mattress (n = 35, med NRS 3 (IQR 0;8)). Moderate or severe pain (NRS 4-10) was infrequently reported following most investigations or procedures with the exception of urinary catheter (60.8%), cervical collar (54.9%) and immobilization mattress (48.5%). Cervical collar induced severe pain in 41.8% of the patients. Conclusion: Most investigations and procedures commonly administered in the ED to older adults are associated with no pain or low intensity of pain. Severe pain is also infrequently induced by these interventions for most older adults. However, urinary catheter, cervical collar and immobilization mattress are associated with a higher intensity of pain and more than 40% of patients suffering from severe pain following the application of cervical collar. Considering the potential adverse effects of pain and the lack of evidence-based data to support the use of some interventions such as the cervical collar, the decision to use these interventions should be carefully weighted and could include a shared-decision making process. The generalizability of those findings to older adults with cognitive impairment is unknown. Future studies should focus on circumstances in which these procedures are beneficial to the patient to limit the unnecessary pain associated with their use.