Abstract: A waterbed retention system. The system includes a stabilizing device that is carried by each side frame member of the bed being disposed above the space formed between the respective frame members and the mattress of the bed. A retaining device is fitted over the side edge of the sheet being removably secured thereto lengthwise thereof. The retaining device and the sheet are received between the frame member and the mattress, so that it can pivot slightly in the space below the stabilizing device to accommodate movement of the sheet due to stress thereon during normal use of the waterbed. This also permits the retaining device to thereafter pivot back to its normal position under the influence of the mattress, so that once the stress on the sheet is removed, the sheet will be retained on the mattress and will return to its normal smooth position without being substantially creased and without requiring frequent remaking of the bed.