This study was designed to examine whether rat spermatozoa after freeze-drying and 1-year storage can participate in full-term development following intracytoplasmic sperm injection (ICSI). Cauda epididymal spermatozoa from Crlj:Wistar rats were frozen in liquid nitrogen (LN 2 ), first dried for 14 hr at 0.37 hPa and then for 3 hr at 0.001 hPa. The dried spermatozoa were stored for 1 year in a desiccator at þ258C, or in a refrigerator at þ48C, or in LN 2 at À1968C. Controls consisted of sperm that had only been frozen and stored in LN 2 . After being stored, spermatozoa were sonicated to dissociate the sperm tail and were injected into oocytes from superovulated Slc:SD rats. The respective fertilization rates of oocytes injected with frozen sperm, or with freeze-dried sperm stored at þ25, þ4, and À1968C were 79%, 75%, 70%, and 73%. However, the corresponding cleavage rates of injected oocytes were 63%, 1%, 38%, and 36%. After transfer of >80 zygotes of each group into recipients, the respective percentages of full-term normal offspring resulting from frozen sperm or from freeze-dried sperm stored at þ25, þ4, and À1968C were 36%, 0%, 7%, and 14%. These results demonstrate that the storage temperature significantly influenced the likelihood of term development of rats produced by injection of oocytes with freezedried spermatozoa. Chromosomal analysis of the rat spermatozoa in the ICSI oocytes indicated that chromosomal aberration in freeze-dried spermatozoa stored at þ258C (100%) occurred more frequently than in frozen control spermatozoa (41%) and freezedried spermatozoa stored at À1968C (35%), and the frequency of chromosomal aberrations in freezedried spermatozoa stored at þ48C (65%) was the intermediate. In conclusion, rat spermatozoa freezedried and stored at þ48C for 1 year are capable of participating in full-term development after ICSI. Mol. Reprod. Dev. 75: 890-894, 2008.