The paper includes temperature measurement results on hybrid microelectronic circuit surfaces carried out by infrared microscope with special attention to critical temperatures (hot spots) which may require hybrid microelectronic circuit redesign. Critical component reliability analysis, as well as the need for replacement with more reliable components is considered. The principle for hybrid microelectronic design verification suggested.The paper is the result of longterm efforts at the Rudi Čajavec Factory in Banja Luka, where we have been investigating the possibilities for very reliable hybrid microelectronic circuit design.