To study the effects of time and temperature on attachment of tissue sections to microscope slides, we examined the intensity of immunohistochemical staining of selected antigens in nine different neoplastic and normal tissues after attaching sections at different times and temperatures. Typically, both the temperature and time are minimized when tissue sections attached to slides; however, suboptimal times and temperatures during attachment may result in either loss of tissue due to poor attachment or the necessity for inconvenient staining regimens. Using standard immunohistochemical techniques, 5 μm tissue sections were attached at 58 °C for 1, 4 and 24 hr. In a separate study, 5 μm tissue sections were attached for 16 hr at 58, 68 and 80 °C. The intensity of staining decreased slightly when the tissue sections were heated at 80 °C for 16 hr, but there was little or no decrease when tissues were heated at 68 °C or lower for 16 hr, or at 58 °C for up to 24 hr.