Here we have presented an electrochemical assay, termed ELIDIS, for ultrasensitive detection of specific antibodies that combines the programmability and versatility of antibody-responsive DNA-based devices with those of enzymatic amplification. More specifically, ELIDIS is a two-step assay that uses antigen-conjugated DNA strands and enzyme-DNA hybrids for the electrochemical detection of multiple target antibodies. The platform provides detection limits in the pM range, is specific (no signal is observed in the presence of nontargeted antibodies), and works well also in 80% of serum. A direct comparison with a commercial ELISA kit shows that ELIDIS is competitive in terms of sensitivity, assay time, cost, and simplicity of reaction steps (scheme S1). It was not possible to directly compare our approach with chemiluminescence assay (CLEIA) as no commercial kits were available for the same target antibodies we tested here. Despite this, considering the reported sensitivities for similar protein targets it is likely that CLEIA can provide a slightly better sensitivity than ELIDIS.