Abstract: A spacer-tray loading machine loads cans or other containers into nestable spacer trays. The spacer trays are shaped with a plurality of container-bottom receptacles in a row-column array and nest together when empty to form a stack. The spacer-tray loading machine comprises a multiple-lane container feeder for supplying containers arranged in parallel rows to a tray loading area of the machine. The number of lanes equals the number of columns of container-bottom receptacles in the spacer tray. The spacer-tray loading machine further comprises a stacked-tray supply conveyor for advancing a horizontal stack of trays towards a tray-withdrawal end of the stack.