While γ-glutamylcyclotransferase (GGCT) has been implicated in cancer-cell proliferation, the role of GGCT enzymatic activity in the regulation of cancer-cell growth remains unclear. Toward further understanding of GGCT in vivo, here we report a novel cell-permeable chemiluminogenic probe "MAM-LISA-103" that detects intracellular GGCT activity and apply it to in vivo imaging. We first developed a chemiluminogenic probe LISA-103, which simply and sensitively detects the enzymatic activity of recombinant GGCT through chemiluminescence. We then designed the cell-permeable GGCT probe MAM-LISA-103 and applied it to several biological experiments. MAM-LISA-103 successfully detected the intracellular GGCT activity in GGCT-overexpressing NIH-3T3 cells. Moreover, MAM-LISA-103 demonstrated tumor-imaging ability when administered to a xenograft model using immunocompromised mice inoculated with MCF7 cells.