In this work, two hydrogels were developed as cationic dye adsorbents. Polyacrylamide / Polyvinyl alcohol (PAM/PVA) composite matrix was prepared via in-situ polymerization reaction. Then, the obtained hydrogel was modified with 0.12 wt.% of calcium carbonate nanoparticles (CaCO₃), previously precipitated in a carbonate solution and modified with stearic acid, (PAM/PVA/CaCO₃). The prepared nano-particles were investigated with X-ray diffraction (XRD) and transmission electron microscope (TEM). Moreover, the obtained hydrogels were characterized with scanning electron microscope (SEM) and Fourier transform infrared (FTIR) compared with the incorporated carbonate nanoparticles. The results confirmed the successful preparation of PAM/PVA hydrogel and the efficient inclusion of CaCO₃ nanoparticles in the composite matrix. The removal of methylene blue with PAM/PVA was ~ 50 % using 2 gm after 60 min.  at pH8. Meanwhile, one gram of PAM/PVA/CaCO₃ exhibited ~ 27 % at pH 2 and pH 12 after 30 min. which emphasized its capability to remove the dye in the acidic and the alkaline medium. No doubt, the developed hydrogels can be employed in the wastewater treatment.