Highly porous 45S5 bioactive glass-based scaffolds prepared by foam replication method were coated with cellulose nanowhiskers by dip coating method. The obtained cellulose nanowhisker-coated scaffolds retained the high porosity and interconnected pore structure. The cellulose coating improved the mechanical properties of the scaffolds and did not hinder their bioactivity in simulated body fluid. In vitro biocompatibility assessment was carried out by qualitative evaluation of the morphology of osteoblast-like cells (MG-63) seeded onto the scaffolds. The cells were shown to attach and spread on both uncoated scaffolds and cellulose nanowhisker-coated scaffolds, thus cellulose nanowhisker coating seems to have no negative influence on the behavior of MG-63 cells. The obtained bioactive and biocompatible composite scaffolds represent promising candidates for bone tissue engineering applications.