The aim of this study was to clinically evaluate the use of alloderm to increase the width of attached gingiva. Nine patients were selected. The inclusion criteria were: attached gingiva smaller than 1 mm; Miller's class I and II gingival recession; patients able to attend control dental appointments; absence of periodontal pocket and endodontic treatment in the neighboring area where the acellular dermal graft would be placed. The clinical evaluation included: allograft shrinkage 7, 14, 21, 30, 60 and 90 days after surgery; width of attached gingiva at the end of the study; difference in color and mobility of allograft. Allograft shrinkage was calculated by comparing its area immediately after surgery to its areas in the other days. Five standardized photographs were taken, digitized and the allograft area was measured. Paired Student's t-test was used to compare the clinical data (alpha=0.05). The mean allograft shrinkage 90 days after surgery was 90.43% and the mean width was 1.27 mm. Difference in color was observed in only 1 subject and no allograft mobility was detected. The results showed a large shrinkage of allograft 90 days after its insertion, raising doubts as to its validity for increasing the width of attached gingiva.