Cysteine engineered anti-MUC16 antibodies are engineered by replacing oneor more amino acids of a parent anti-MUC16 antibody with non cross-linked, reactivecysteine amino acids. Methods of design, preparation, screening, and selectionof the cysteine engineered anti-MUC16 antibodies are provided. Cysteine engineeredanti-MUC16 antibodies (Ab) are conjugated with one or more drug moieties (D)through a linker (L) to form cysteine engineered anti-MUC16 antibody-drug conjugateshaving Formula I: Ab- (L- D)