More than 1/3 of back injuries among nurses result from patient transfers. So, a rigorous between-subjects quasi-experimental methodology having broad clinical applicability was developed to evaluate the effects of a one-hour didactic back safety and patient transfer training lecture/demonstration upon 42 recently hired hospital nurses. The design implemented independent random samples including independent control groups, though practical constraints required all 42 to participate in the training. Training effects were assessed for each of three back safety transfer skill self-efficacy measures and their composite total self-efficacy score. Four monthly training sessions, each serving different nurses, achieved significant and substantial impacts on both composite total back safety procedure self-efficacy (where effect sizes ranged from approximately 0.8 to 1.8 standard deviations) and on each individual back safety transfer skill self-efficacy measure. After training, 85% to 100% of the nurses rated their back safety procedure self-efficacy within three points of the maximum composite total of 30 on the self-efficacy scale. Results may help improve nursing services and identify training strategies to reduce healthcare worker back injuries.