This study was conducted to examine the expression of tumor necrosis factor receptor type1 (TNFR-I) on granulosa cells of pre-ovulatory follicles in sheep. In all ewes (n=15), estrus was synchronized with the Controlled Internal Drug Release CIDR (12 day). The granulosa cells were collected from pre-ovulatory follicle 48 hours after CIDR withdrawal. Expression of mRNA was investigated using a reverse transcriptase-polymerase chain reaction (RT-PCR). Total RNA was extracted from cells and then reverse-transcribed to synthesize cDNA and PCR-amplified using specific oligonucleotide primers. Result of present study indicates TNFR-1 was not expressed at the mRNA level. In general, this finding provides further insight into the proposed physiologic roles of TNFα in ovarian function.