The invention is directed to a method and system for efficiently distributing Inverse Multiplexing over ATM (IMA) filler cells on IMA logical links having inactive or unusable IMA sub-links. Inactive IMA sub-links are identified during round-robin distribution of ATM data cells to active IMA sub-links. Predefined IMA filler cells are transmitted simultaneously on the identified inactive IMA sub-links when an ATM data cell is transmitted on an active IMA sub-link, thereby reducing the delay between transmitting ATM data cells.