In this VETgirl online veterinary continuing education podcast, we review the use of combining serum anti-Müllerian hormone (AMH) and progesterone (P4) levels when diagnosing canine ovarian remnant syndrome (ORS). ORS is a condition in which ovarian tissue is left behind after a female dog has been spayed. Unfortunately, when this happens, the tissue can continue to release hormones that manifest clinically as signs of estrus. As many of our small animal clinicians have learned, suspecting ORS can be easy at times, but diagnosing ORS can prove quite challenging! The diagnostic options for ORS, including vaginal cytology, estrogen levels, various stimulation and other hormonal tests, luteinizing hormone (LH), and imaging, can be overwhelming and possess individual limitations.