The prupose of this study was to investigate in vitro the adaptation and condensation of the proximal section of amalgam restorations placed in Class II preparations of conventional and conservative designs. The amalgam restorations were placed with traditional hand instruments with and without the aid of an automatic amalgam condenser. The restorations and sections of the restored teeth were examined and scored for adaptation and porosity. The restorations in the preparations of conservative design, especially those placed without the aid of the automatic condenser, exhibited more adaptation defects, porosity, and voids than did the restorations in the preparations of conventional design. It is necessary to identify and describe instruments and technqieus that will facilitate the placement of amalgam restorations in preparations with limited access.