An insulating compartment is combined with a type grocery cart characterized by an open basket having forwardly-tapering sidewalls and bottom wall which terminate in a common front wall, as well as having a top-hung rear flap-panel that swings up when the nose of a like grocery cart's basket pushes inside from the rear to enter and dock inside the basket space of the first grocery cart. The insulating compartment is limited in extent to generally the front portions only of the grocery cart's basket. Preferably, the insulating compartment comprises a front wall that matches flush against substantial portions of the basket's front wall. It also comprises abbreviated sidewalls and bottom wall arranged to match flush against front portions of the basket's sidewalls and bottom wall. Thus, the insulating compartment provides insulation service to cold or frozen food and beverage merchandise during grocery shopping trips.