Seminal plasma (SP) is thought to protect sperm from damage caused by cooling or freezing. We tested the concept with emu sperm and found that SP improved Viability, motility and fertilising ability. Moreover, the SP from some males was more effective than the SP of others. When we separated SP into high-molecular weight (HMWF) and low-molecular weight (LMWF) fractions, we found that HMWF was more effective than LMWF. We conclude that SP can protect emu sperm during in vitro storage and the components responsible should be identified so they can be used in reproduction management.