Access block, the inability of patients in the emergency department (ED) to access hospital beds, is a contributing factor to overcrowding in the ED. The effect of a holding unit (HU) on access block and some medical management indicators is presented. In October 2002 an HU was opened with 16 beds for patients coming from the ED. Every morning all the patients are moved from the HU to a conventional unit; if there are not enough unoccupied beds, elective admissions are cancelled. For the previous and subsequent years after the opening of the HU, the following factors were analysed: (1) number of patients visiting the ED; (2) number of urgent admissions; (3) length of stay in the ED; (4) number of patients waiting for an in-hospital bed in the ED at 08.00 h; (5) number of elective admissions; and (6) number of cancelled elective admissions. Although there was an increase of 3.1% in the number of patients visiting the ED during the first year following the opening of the HU compared with the previous year, the number and percentage of urgent admissions remained unchanged. In the same period the mean number of patients waiting for a bed in the ED decreased by 55.6% (9.1 vs 4.0 patients per day). However, the mean length of stay in the ED increased by 6.9% (p<0.001). The number and percentage of cancelled elective admissions were similar in the two periods of the study. The opening of an HU has led to an improvement in the access block.