Like adults, infants use working memory to represent occluded objects and can update these memory representations to reflect changes to a scene that unfold over time. Here we tested the limits of infants' ability to update object representations in working memory. Eleven-month-old infants participated in a modified foraging task in which they saw 2 quantities of crackers sequentially hidden in buckets and then were allowed to choose between them. We manipulated the working memory demands of the task by either hiding crackers in direct succession (i.e., infants saw all of the crackers hidden in the first location, then saw all of the crackers hidden in the second location), or hiding them in alternation (i.e., infants saw some crackers hidden in the first location, then saw some crackers hidden in the second location, then saw more crackers hidden in the first location). Across 6 experiments we found that infants successfully updated their representations of the hidden arrays when crackers were presented in succession. However, when crackers were hidden in alternation and infants had to reupdate an array that was no longer in the current focus of attention, infants showed a striking pattern of failure. These results suggest that, for infants as well as for adults, the flexibility of working memory is subject to processing constraints. (Contains 2 figures and 3 footnotes.)