Objective: To search for novel peptides and common binding motif that specifically bind to endometriosis. Design: Prospective study. Setting: Department of Biological Science and Technology in national university. Patient(s): Specimens were divided into  ectopic endometrium (n = 10);  eutopic endometrium (n = 10). Intervention(s): Peptides specifically binding to endometriosis are screened from a phage-displaying peptide library (Ph.D.-12) by using whole-cell screening technique after an adsorption elution amplification procedure. Main Outcome Measure(s): Combinatorial peptide libraries were used to identify small molecules that bind with high affinity to receptor molecules and mimic the interaction with natural ligands. Few pans of positive phage clones with significantly positive signals were identified by ELISA and analyzed by DNA sequencing. Result(s): During the biopanning processes, the recovered phage number (106 pfu/mL) in parts 1, 2, 3, 4, and 5 of the study were 9, 33, 82, 142, and 169. Nine phages consistently had residue Arg, whereas six clones had a consensus motif of Arg-X-Arg-X-X-X-X-Arg. The biotin-labeled peptide bound to endometriosis cells in a dose-dependent manner, yet the control peptide revealed lesser binding activity. Conclusion(s): The novel motif is associated with higher affinity of endometriosis, which might be useful in endometriosis targeting and as potential antiendometriosis therapies. We provide one potential approach for novel therapies toward endometriosis.