The research aimed to study estrus synchronization response on reproductive performance of Madura cattle (i.e. native cattle in Madura Island of Indonesia) with different body condition score (BCS). Field research was conducted using 42 cows which were purposively selected from small holders farmers and grouped into 4 BCS  (<2.5, 3.0, 3.5, and >4.0). Number of cows in each BCS was 9, 12, 12 and 9 heads, respectively, with the average open days of 156.76+79.19 days. Synchronization was performed by PGF₂α double injection (Glandin, GmB). Variables observed were estrus onset and Non Return Rate (NRR) after Artificial Insemination (AI) followed by pregnancy diagnosis. Result of this research showed that Madura cow had significant problem of low body weight and BCS. The success of estrus synchronization and NRR after AI on each BCS were 77.77, 66.67, 91.66, 66.67% and 66.67, 52.83, 75.0, 66.67%, respectively. Interval from PGF2α  injection to estrus onset  was 69.55+7.28, 64.36+8.09, 58.90+8.04 and 63.35+10.86 hours.  All parameters showed non-significant difference.

Key words: AI, BCS, Estrus synchronization, Madura Cattle