Twenty-one soluble proteins, five tRNAs, and three protein-nucleic acid complexes were studied in a systematic manner with regard to their crystallization behavior from polyethylene glycol and ammonium sulfate solutions in the presence of 0 to 1.5% beta-octyl glucoside. Our observations suggest that this neutral detergent does influence in a very positive way the growth characteristics of the macromolecules included in this experiment. In general, more reproducible and rapid growth was noted with an increased number of large individual crystals at the expense of microcrystals. In several cases, new crystal forms were discovered. Selected x-ray diffraction analyses imply that crystals grown in the presence of beta-octyl glucoside diffract as well or better than those grown in its absence. In addition, a screen of two proteins grown in the presence of 14 different common detergents suggested that a general detergent effect may be beneficial for the growth of crystals of biological macromolecules.