A scanning electron microscope (SEM) survey assessed the quality of ultrastructural preservation of a wide range of tissues from the laboratory rat and from a limited number of botanical and fly-larval samples, air-dried from tetramethylsilane (TMS) after chemical fixation and dehydration. Comparisons were made with critical point drying (CPD) and air-drying from acetone. CPD produced good results in all cases. TMS gave acceptable results with 75%, and acetone with 31%, of rat tissues. Air-drying was unacceptable for the botanical and fly-larval samples. It is concluded that air-drying from TMS is generally useful for mammalian tissues in preparation for the SEM.