Phlebotomy is one of the common invasive procedures carried out all round the globe. The practice of phlebotomy varies widely. In terms of the technique, the procedure may involve the use of a syringe or a vacutainer, and as for the technicians, some are not specifically trained to perform the procedure and others are qualified phlebotomists. Finally, some may receive training on the job, while others undergo formal, focused training. However, the underlying ethical principles of respect for autonomy and informed consent do not change. This commentary, which is supported by data collected during training in phlebotomy, reflects on the ethical issue of obtaining consent for the procedure.