The purpose of this study was to compare extraction sites augmented with bovine bone mineral (BBM) with and without resorbable membrane coverage. BBM particles were grafted in fresh human extraction sockets of 23 patients; in 12 of these patients, a guided tissue regeneration (GTR) membrane was applied. After 9 months of histomorphometric evaluation, cylindric hard tissue specimens were obtained. Percent bone area fractions (BAFs) of the crestal, middle, and apical sections from each specimen were calculated using the point-counting technique. Changes in values were compared. In sites augmented with BBM, the mean BAF ranged from 22.8% (coronal) to 36.3% (apical) compared to sites augmented with BBM and collagen membrane (35.2% [coronal] to 47% [apical]). Comparison between the different depths and the two groups showed a distinct increase in BAF from coronal to apical regions (P .001). This pattern was observed in both groups (P .001) and was significantly higher in the group augmented with BBM and collagen membrane (P .05). In the immediate postextraction phase, BBM as a grafted biomaterial preserved the socket volume and enabled newly formed bone for future implant site preparation. The amount of the osseous fraction increased with GTR membrane.