Non-frozen storage of sperm for several weeks was achieved by the use of buffered protective agents and low temperature. For example, sperm stored with 5% dimethyl sulphoxide at −4.5 C for 28 days gave 81% fertility; use of 5% ethylene glycol allowed storage at −3 C for 38 days, giving 70% fertility. It is suggested how these results may be employed for interspecific mating of salmonids. Attempts to employ glycerol as a protective agent were unsuccessful as were all attempts at freezing sperm.The necessity of providing an adequate air-space in vials used for short-term storage of undiluted sperm of Atlantic salmon is demonstrated.Although a rough correlation between motility of sperm and fertilization is reported, caution in the interpretation of motility as an indication of fertility is suggested.