Summary: This study examined the impact of water storage over 3 months on the creep deformation of different CAD-CAM composite structures at both the nanoscale and macroscale. Seven CAD-CAM blocks were tested, including resin-composite blocks, a polymer-infiltrated ceramic network (PICN) block, and a ceramic-filled polyetheretherketone (PEEK) block. Nano-indentation creep measurements were conducted using a nanoindenter, with results showing increased creep depth after water storage. The PICN material exhibited superior dimensional stability, while other composite blocks showed increased creep after water storage. Significant differences were observed between storage conditions and materials, with correlations identified between creep depth, filler weight%, and bulk compressive creep.