In this study, effect of acupuncture (AP) on the luteal size (LS), luteal blood flow (LBF) and progesterone (P4) levels were investigated in the presence of corpus luteum (CL) in cows. Seven days after 14-days interval PGF2a estrus synchronization protocol, CL positive animals were assigned either to a control group (AP-, n=10) or to an AP group (AP+, n=10) stimulated by using B22 and B23 sensitive acupoints. LS and LBF examinations were carried out before the stimulation (0h) and at 1st, 3rd, 6th hour on d7 and thereafter on d9, d10, d11, d12 and d13 following the AP stimulation in each group with a portable color Doppler ultrasonography. Blood samples for P4 measurement were collected during each examination. There was no significant difference in LS, LBF, or P4 mean values between groups. However, LBF significantly increased at 6h after stimulation (P<0.05) in AP+ group but it increased at d11 in AP-group (P<0.05). The significant increase in LS was observed earlier in AP+ group (on d9; P<0.01) than AP-(on d11; P<0.05). Serum P4 concentrations increased at 3h, d9 and d10 in AP+ group (P<0.05), however a significant difference was only observed at 3h in AP-group (P<0.05). In conclusion, AP stimulation induces earlier increases in LS, LBF and P4 parameters in cows during luteal phase.