Introduction: The choice of weight estimation method to use during prehospital paediatric emergency care is important because it needs to be both accurate and easy to use. Accuracy is important to ensure optimum drug dosing while ease-of-use is important to minimise user errors and the cognitive load experienced by healthcare providers. Little is known about which weight estimation systems are used in the prehospital environment anywhere in the world. This knowledge is important because if the use of inappropriate weight estimation practices is identified, it could be remedied through education and institutional policies. Methods: This was a prospective questionnaire study conducted in Johannesburg, South Africa, which obtained information on the knowledge, attitude and practice of weight estimation amongst advanced life support (ALS) paramedics. Results: Forty participants were enrolled, from both the public and private sectors. The participants’ preferred method of weight estimation was visual estimation (7/40; 18%), age-based formulas (16/40; 40%), parental estimation (3/40; 8%), the Broselow tape (2/40; 5%) and the PAWPER tape (11/40; 28%). No participant was familiar with or used the Mercy method. All participants were very confident in the accuracy of their selected system. Discussion: The knowledge and understanding of weight estimation systems by many advanced life support paramedics was poor and the use of inappropriate weight estimation systems was common. Further education and intervention is needed in order to change the sub-optimal weight estimation practices of ALS paramedics in Johannesburg. Keywords: Weight estimation, Paediatrics, PAWPER tape, Broselow tape