AbstractHigh-resolution immunolight microscopy was carried out on a series of neoplasms embedded in Spurr plastic by means of computerized robotic capillary action. The techniques and computer program are delineated. The results demonstrate the highly resolved immunostaining with low background attained in plastic sections. Tissues were dewaxed, reembedded in Spurr, and reacted on the autostainer with no qualitative loss of immunoreactivity. Advantages of employing the autostainer include quality control (both positive controls and unknowns can be immunoreacted in tandem), ability to carry out immunoreactions on different cases at the same time, use of far less quantities of antibody and reagents than for manual procedures, and better use of technologist time (other laboratory procedures can be done while the sections are being robotically stained). (The J Histotechtzol13:249, 1990)