Monoclonal antibodies (MAbs) against Lv were specific and sensitive to Vtg. Two MAbs recognizing different Vtg epitopes were screened from anti-Lv MAbs. A sandwich ELISA for zebrafish Vtg was developed using anti-Lv MAbs. MAbs-based sandwich ELISA had higher sensitivity than ELISAs using PAbs. Estrogenic activity of 17β-estradiol was detected by the anti-Lv based ELISA.