We report our initial experience with 302 consecutive cases of percutaneous cardiac catheterization in in-patients from other hospitals. The patients reached our laboratory immediately before the procedure in an ambulance with an attending physician and were transported back to their hospital soon after completion of the procedure. This accounts for 35% of 864 diagnostic cardiac catheterization procedures in our laboratory in the first 12 months of activity. There were no complications related to this regimen, and a substantial reduction in unnecessary overnight admission to the cardiology ward was achieved. This report confirms the safety and the advantages of this practice. Implications for the organization of the catheterization laboratory are discussed.