The sera of active and treated cases of kala-azar were tested for circulating immune complexes (CIC) by antigen-specific enzyme linked immunosorbent assay (ELISA). All (100%) of proved cases had elevated CIC; 64.3% of clinically diagnosed cases and 58.8% of treated cases were also positive for CIC. A fall in the level of CIC was observed after treatment. Detection of antigen-specific CIC may be useful in monitoring the therapeutic effect and recovery.