A method of screening solution conditions suitable for the crystallization of macromolecules with a picogram to a microgram of protein using picoliter or nanoliter volumes is provided. A preferred method comprises preparing a plurality of recipe solutions in milliliter volumes, aspirating protein and recipe solutions, respectively, from a plurality of wells, and dispensing the protein and recipe solutions into a plurality of wells, covering the combined protein and recipe solutions with oil, and maintaining the solution wells until crystallization or precipitation occur therein.