Techniques were developed that resulted in the fertilization of fresh eggs of spring chinook salmon (Oncorhynchus tshawytscha) and coho salmon (O. kisutch) with sperm frozen 7 days in liquid nitrogen (−196 C). Maximum fertilities obtained were 38 and 79%, respectively. Best results for coho salmon were achieved when mannitol and dimethyl sulfoxide were included in the extender, and when no time was allowed for equilibration of the fresh sperm to the extender. This is the first success reported in preserving viable sperm of these two species at subfreezing temperatures.