The invention provides antibodies, and antigen-binding fragments thereof, that specifically bind to a polypeptide, or antigenic portion thereof, wherein the polypeptide is selected from a) MUC16 ectodomain polypeptide, b) MUC16 cytoplasmic domain polypeptide, and c) MUC16 extracellular domain polypeptide that contains a cysteine loop polypeptide. The invention's antibodies and compositions containing them are useful in diagnostic and therapeutic applications for diseases in which MUC16 is overexpressed, such as cancer.