Factors affecting the cryopreservation of immature embryos of Triticum aestivum (wheat), embryogenic calli of a Saccharum hybrid (sugarcane) and cell suspension cultures of Panicum maximum (Guinea grass) and Pennisetum glaucum (= P. americanum, pearl millet) were optimized. Fertile plants were recovered from immature embryos of wheat which had been cultured for 3 days and then cryopreserved. Use of a single cryoprotectant, rather than a mixture, was better. Cryopreservation of sugarcane callus was substantially improved by including a pregrowth period in liquid culture medium supplemented with 0.33 M sorbitol and avoiding post-thaw removal of cryoprotectants. Plant regeneration from cryopreserved calli was similar to that from unfrozen controls. Survival rates of 100% and 92% (by TTC assay) were obtained from suspensions og Guinea grass and pearl millet, respectively, which had been pregrown in media supplemented with 0.33 M mannitol for 3 days and cryoprotected by the gradual addition of 0.5 M sorbitol and 0.7 M dimethylsulfoxide (DMSO). No reduction in viability was observed in cells stored in liquid nitrogen for up to 3 years.