An improved glucose‐chelator‐albumin bioconjugate (GluCAB) derivative, GluCAB‐2Mal, has been synthesized and studied for in vivo 64Cu‐PET/CT imaging in breast cancer mice models together with its first‐generation analogue GluCAB‐1Mal. The radioligand works on the principle of tumor targeting through the enhanced permeability and retention (EPR) effect with a supportive role played by glucose metabolism. [64Cu]Cu‐GluCAB‐2Mal (99 % RCP) exhibited high serum stability with immediate binding to serum proteins. In vivo experiments for comparison between tumor targeting of [64Cu]Cu‐GluCAB‐2Mal and previous‐generation [64Cu]Cu‐GluCAB‐1Mal encompassed microPET/CT imaging and biodistribution analysis in an allograft E0771 breast cancer mouse model. Tumor uptake of [64Cu]Cu‐GluCAB‐2Mal was clearly evident with twice as much accumulation as compared to its predecessor and a tumor/muscle ratio of up to 5 after 24 h. Further comparison indicated a decrease in liver accumulation for [64Cu]Cu‐Glu‐CAB‐2Mal.