Visual-spatial ability is thought to be important in competency in specific surgical procedures. To test this hypothesis, 37 surgical residents completed six tests of visual-spatial ability, ranging from low-level to high-level visual processing. Using previously validated and objective instruments, we then assessed their ability to complete and learn a spatially-complex surgical procedure. Residents with higher visual-spatial scores in the form-board test and the mental-rotations test did significantly better in the procedure than did those with lower scores. After practice and feedback, residents with lower scores achieved a comparable level of competency. Our results suggest that visual-spatial ability is related to competency and quality of results in complex surgery, and could potentially be used in resident selection, career counselling, and training.