To evaluate the effects of adding vibrotactile feedback (VTF) in myoelectric prosthesis users during performance of a functional task when visual feedback is disturbed. A repeated-measures design with a counter-balanced order of 3 conditions. Laboratory setting. Transradial amputees using a myoelectric prosthesis with normal or corrected eyesight (N=12, median age 65±13y). Exclusion criteria were orthopedic or neurologic problems. All participants performed the modified Box and Blocks Test, grasping and manipulating 16 blocks over a partition using their myoelectric prosthesis. This was performed 3 times: in full light, in a dark room without VTF, and in a dark room with VTF. Performance time, that is, the time needed to transfer 1 block, and accuracy during performance, measured by number of empty grips, empty transitions with no block and block drops from the hand. Significant differences were found in all outcome measures when VTF was added, with improved performance time (4.2 vs 5.3s) and a reduced number of grasping errors (3.0 vs 6.5 empty grips, 1.5 vs 4 empty transitions, 2.0 vs 4.5 block drops). Adding VTF to myoelectric prosthesis users has positive effects on performance time and accuracy when visual feedback is disturbed.