The effect of different macromolecules [bovine serum albumin (BSA), Pluronic F-68, (ET surfactant), or sodium hyaluronate (SH)] on postthaw survival of mouse morulae and in vivo- and in vitro-derived bovine blastocysts frozen in 10, 5, or 1% glycerol solutions was investigated. Embryos were equilibrated with cryoprotectant solution at 25°C for 10 min, seeded at −5°C, cooled at 0.5°C/min to −35°C, and plunged into liquid nitrogen. Embryos were thawed in a 35°C water bath, glycerol was removed with 0.6 M sucrose at 25°C for 5 min, and postthaw viability was evaluated after 1, 24, and 48 h in culture. The addition of BSA supplementation improved postthaw survival of mouse morulae frozen in 5% glycerol, but not in 10% glycerol. All three macromolecular supplements were effective in increasing survival of mouse morulae in 5% glycerol but only BSA and SH were effective in increasing postthaw survival of in vivo- and in vitro-derived bovine blastocysts. None of the macromolecular supplements improved postthaw survival of embryos frozen in 1% glycerol.