We describe a contact printing approach for microarrays that uses fused-silica capillary tubes with tapered tips for printing pins and a pressure/vacuum system to control pin loading, printing, and cleaning. The printing process is insensitive to variable environmental factors such as humidity, and the small diameter of the pins allows routine printing from 1536 well source plates. Pin load capacity, 0.2 microL in the current system, is adjustable by controlling pin length. More than 2000 spots can be printed per 0.2-microL pin load (<100 pl/spot), and densities of >12,000 spots/cm(2) are readily achievable. Solutions with a wide range of viscosities and chemical properties can be printed. The system can print tens of thousands of different solutions at high speed, due to the ability to use large numbers of pins simultaneously, and can produce a large number of replicate arrays since all of the solution picked up by the pins is available for deposition.