Seven formalin-fixed, paraffin-embedded heart specimens set up at autopsy performed from 3 to 18 years before analysis of newborns in which DiGeorge syndrome (DGS) was suspected were evaluated by fluorescence in situ hybridization (FISH) using a DGS region-specific probe and a control probe on nuclei released from thick sections. The diagnosis was confirmed in four of the six specimens, which provided valuable results, and in none of the controls. This study supports the feasibility and usefulness of FISH genotyping of archival autoptic material, which improves and assists the counselling procedures.