The design and generation of disulfide-stabilized Fv fragments (dsFv’s) addresses stability and aggregation problems that are frequently associated with single-chain Fvs. VH and VL of dsFv’s are connected by an interdomain disulfide bond. To generate such molecules, one amino acid each in the framework region of in VH (at position 44) and VL (at position 100) are mutated to a cysteine, which in turn form a stable interchain disulfide bond. The resulting dsFv’s (no linker peptide) or scdsFv (linker as well as interchain disulfide bond) can be easily produced in various expression systems. Disulfide-stabilized Fv’s solve most problems that are frequently associated with Fvs or scFvs; they are very stable and in most instances show full antigen binding activity.