This paper analyzes the worst-case performance of combinations of greedy heuristics for the integer knapsack problem. If the knapsack is large enough to accomodate at least m units of any item, then the joint performance of the total-value and density-ordered greedy heuristics is no smaller than . For combinations of greedy heuristics that do not involve both the density-ordered and total-value greedy heuristics, the worst-case performance of the combination is no better than the worst-case performance of the single best heuristic in the combination.